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What Does “Not Responding” Mean?

Bad behavior on someone’s part.

"Not Responding" is Windows' way of telling you that a program might have a problem. Sometimes it's benign and sometimes it's a sign of a deeper issue.
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Question: I am having difficulty when I am browsing or using a program. After a few minutes the computer freezes and I get a message in parenthesis saying (Not Responding). Sometimes I have to log off and log on again to fix this problem. But after a few minutes it happens again. How can I fix this?

“(Not Responding)” appears in the title bar of a program when Windows detects that the program isn’t behaving properly. Exactly why depends on the specific program and what you were doing at the time.

Let’s look at some of the possibilities, which range from software or hardware problems to user impatience.

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Not responding

“Not responding” happens when a program stops interacting with Windows properly. This can be due to legitimate delays, if the program is busy working, or to errors like a programming bug, design error, hardware problem, malware, and more.

Programs are expected to respond to Windows

Windows expects programs to respond to its requests in a timely fashion.

If you type a key and the program you’re using doesn’t take it because it’s too busy doing something else, that’s not responding. If you click on the Close Program “X” on a program’s window and the program doesn’t acknowledge it, it’s not responding.

When Windows asks a program to do something like take a keystroke or close itself, and the program fails to acknowledge the request within a certain amount of time, the program is classified as not responding, and Windows indicates that in the title bar of the program.

If the program never comes out of that state, we also call it hung, as in hung up on something.

Legitimate delays

There are legitimate reasons this can happen.

For example, if the program you’re using is doing some very long, CPU-intensive calculation — say a video-editing program performing some operation on a large video or a spreadsheet performing a lengthy calculation — it might not respond in a timely fashion. If you attempt to close the window during that operation or calculation and nothing happens, Windows might eventually add “(Not Responding)” to the title bar. It tried to pass your request to the application, but the app just wasn’t listening.

While it’s bad design not to respond while performing lengthy calculations, it’s also allowed and legitimate. Once the calculation is complete, the program starts listening and responding again.

A different example is a program trying to access something over a network (like the internet). If the connection is bad or the remote server is slow, the program might spend a long time waiting for a reply. During that time, it might well become unresponsive. Once the reply arrives, it becomes responsive once again.

Anything causing an application to stop responding to your input or to Windows’ internal requests can cause “Not Responding” to appear in the title bar.

Not-so-legitimate causes

While lengthy calculations are one semi-legitimate cause, there are other possibilities as well.

  • Programming error. The classic case of an “infinite loop” in programming is perhaps the most common example. If a calculation is mistakenly written so it never ends, and Windows is not given a chance to operate during the calculation, the application may become “hung” and unresponsive. As a user, there’s not much you can do except avoid whatever you did that brought the application to this point.
  • Software design error. This is a variant of the preceding point, but I think of it as a different class of problem. Sometimes a program displays an error message in a pop-up box. While that error message is displayed, the application’s main window stops responding until you dismiss the message. If the message box is displayed off the screen or behind the application’s main window, it will appear as if the application is unresponsive.
  • Hardware. Malfunctioning hardware can, in some cases, cause the software interacting with it to fail in ways making it unresponsive. For example, a USB reader or thumb drive might experience a failure such that the next program to attempt to access it — even just to see if it exists — might end up unresponsive.
  • Hardware drivers. All the hardware on your system is in some way controlled by software. If that software has a bug, even if the hardware is working properly, the result could be a hung application. If hangs appear to be related to interacting with a specific device, it might make sense to make sure you have the latest drivers for that device — not to mention the latest updates for Windows.
  • Malware. Whether intentionally or because it’s poorly written, malware can cause programs, or Windows itself, to become unresponsive. Make sure your security software is running and up to date.
  • Impatience. I’m not trying to “blame the user”, here, but … I have absolutely witnessed people frantically clicking on applications that they believe are taking even the slightest bit too long. The result? It’s often “not responding”. Give the software time to do what you’ve asked it to do.1

Do this

It could be anything.

Pretty vague, I know.

Unfortunately, it’s fairly accurate. The actual cause and solution depends on the specifics of what you’re seeing.

Does it happen all the time, or only when you do certain things? One specific application, or several? All of these things and more are clues necessary to ferret out the cause and come to a solution.

Without more specifics, my general recommendation is to make sure all your software, drivers, and security software is working and up to date.

If the problems persist, try to narrow down the common causes, if any.

Another recommendation? Subscribe to Confident Computing? Less frustration and more confidence, solutions, answers, and tips in your inbox every week.

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Footnotes & References

1: There is, of course, no answer to “how much time?”. It depends on what you’ve asked it to do, the software in question, the machine in question, and more. Use your best judgement. Then maybe add 50%. Smile

36 comments on “What Does “Not Responding” Mean?”

    Hash: SHA1

    Because for those 60 seconds your application isn’t responding.

    Try putting a 1 second delay in a loop of 60 iterations. The performance impact
    will be negligible and Windows should be happier.


    Version: GnuPG v1.4.6 (MingW32)


  2. Hi.

    Firstly, let me thank you, for your reply.

    I followed your suggestion, but, as long as the program is in the 60 iteration for..loop, the application shows not responding in the task manager.
    I noticed one thing though, as soon as the program comes out of the loop the program returns to running state in the task manager.

    Is there any other workaround?


  3. Leo,

    Your article is interesting and helps me understand what might be happening, I wonder if you have missed some other scenario. Many applications are multi-threaded, and as such perform most of their long running or CPU intensive work in a thread that does not interact with the UI. In applications like this, there should be no ‘Not Responding’ scenarios. However, I do see applications that this occur even though they are multi-threaded. Is there any way that the OS is actually causing the application to not respond to the OS’s request to the application?

    In your example, you wrote the application so it was easy to determine the problem. Is there a way to determine what an unresponsive application is doing? In your case, it was network I/O, this would have caused your application to block on the OS’s low level I/O.

    Thanks for any thoughts..

  4. I’ve actually never found a reliable way for non-programmers to answer “what is his application waiting for” when it hangs. The developer, of course, can run the application in a debugger and often see exactly what’s going on, but those resources are not available to the average user.

    Naturally multiple threads need to interact. Typically, if a UI thread hangs even though there’s another worker thread doing the heavy lifting, it’s because the UI thread is in fact waiting for something from that worker thread, or there’s a synchronization problem between the two. (OR there’s something in the UI that needs waiting for.)



  5. I’m not a PC expert, but I’m quite certain that one aspect of this problem is the speed of your broadband connection. I had a very poor download speed with one provider, and switched to BT, paying for its premium broadband service. Now I’ve got it, 20% of all the links I click on, result in ‘this program is not responding’ etc – ie an entirely sudden, new problem I never had before, and without any other changes taking place (eg software, firewall etc). So I do wonder whether my PC is now just trying too hard and too fast for its own good!!?. One thing’s for sure: it ain’t solved easily, because even BT’s own experts can’t tell me whats wrong, and how it might be put right….

  6. An update on my last comment: I SOLVED THE PROBLEM!!! I picked up a tip from another site, which was that McAfee Site Advisor is full of bugs and is prime cause of “this programe is not rsponding”… Sure enough, I disabled McAfee, and in the weeks since, I’ve had absolutely no problems – not one. So if you’ve got McAfee…..that could be your answer…

  7. I have the same problem and now cannot access anything on the computer. In looking for a fix I discovered that this is an ongoing problem since approx. 2004 on tens of thousands of computers, maybe hundreds of thousands, maybe millions, who knows. This is unbelievable. I cannot believe anyone including microsoft has not been able to or willing to fix this problem. If anyone has a fix he/she could probably make a couple million dollars.

    The issue here is that it’s not one problem. “Not Responding” is a symptom that can be caused by any of thousands of different types of problems. As a result it’s not possible to come up with a single fix for this symptom. Each problem must be fixed individually.


  8. I have “RegCure” installed on my computer but I still keep getting the Message “Not Responding” I scan with regcure but its an on going thing.
    Can You Help…….Please?

    Not at all surprised that a registry program would have no effect. This type of problem is rarely registry related. It is, however, related to the SPECIFIC program that’s not responding. There is no single, general, fix.


  9. In IE7, Tools, Internet Options, Programs, Manage Add-Ons, Find Shockwave Flash Object and disable it. It solved my (not responding) problem. Good Luck.

  10. Yes Leo, I totally agreed with you that Not Responding message in title bar is quite legal and legitimate while Windows (especially Vista) is performing lenhthy operation. However, it is indeed an overlook of Miscrosoft in designing an OS (especially a new OS like Vista and Windows 7) without thoroughly consider assigning high enough proirity interrupts to Input/Output devices such as mouse click and keyboard input.

    I have been facing the same “Not Responding” problem with Vista for about a year, and still couldn’t find any solution after so many complaints at many forum sites; e.g.;forums06

    This problem seems very likely to be Vista problem and not the broswer (IE) problem because it also happens to other application like Microsoft Excel especially when Excel is accessing the Internet to retrieve data using WebQuery. If I click a second time on any open program, I get that “Not Responding” error message almost imediately and I have to wait about 10 to 15 seconds. This is not just very frequent, but a sure occurence. It is not a Ram problem either because I have a 3G Ram in my laptop. Very frustrating indeed!
    I kind of agree with someone in a forum saying that it is a problem of Agreesiveness or Too Sensitive (timeout too fast) to this “Not Responding Issue” in Vista though Microsoft may think that it is legimate, which I think is a “Frustrating Legitimacy”! Just wonder why Microsoft is not trying hard enough to resolve this problem after so many complaints in such a long time!

  11. Hello Leo
    I can see by the comments that tons of folk are having the not responding prob on XP, but from what i can see is that we still do not know what to do about it. so, short of reinstalling windows, what do i do about it? can you tell me?

    thanx chilly

    As you’ll see in the article you just commented on, “it could be anything”, so there’s no advice that I can give here that will simply answer “what to do about it”. It depends on all of the specifics of your situation. Reread the article and perhaps you’ll have some ideas of where to look in your situation, but this is a case where there’s little specific “how to fix” advice I can offer.


  12. I run a CADD program that exhibits the exact “Not Responding” behavior you describe while running a legitimate lengthy process. It will start the process and then give the “Not Responding” error after a varying amount of time. Unfortunately the “Not Responding” disables feedback that the program is giving to the screen in it’s own menu system. If left alone the process will finish and the program will return to normal responding state, however it is nice to be able to see the feedback that the program is giving to monitor the process. This only became a problem in Windows 7 and 8 (&8.1). The process runs and responds flawlessly in Windows XP. My understanding is that Windows pings the program and waits for a response, giving the “Not Responding” error if it decides that the program does not respond in a timely manner. My question is can the “Not Responding” ping from Windows be disabled? The processes that the CADD program runs which cause the “Not Responding” can take anywhere from a few minutes to several hours. Thanks!

  13. when I put Avast antivirus on my computer everything changed. My home page looked different at the top, everything started saying, not responding, internet explorer would freeze and say not responding, then it would come back, then it would say Microsoft is not responding, after it comes back then msn or bing is not responding, one after another. I never get to move forward on my computer. could you please give me the steps to remove this Avast antivirus from my computer.

  14. hi, is this a ram problem, almost every program whenever I click on them to select an item or perform a function, they go into not responding hibernation? some longer than others, but almost 90% of my programs.

  15. I am having trouble with all games that I play on GSN. When I finally get one to come on something pops up that says
    Retry/quit game, retry/ok or it might say quit. How can I fix this and my computer is really running slow.

  16. I get a (not responding) message off and on a lot. I live in a subdivision in a condo. I have taken my laptop to two places to fix and it works perfectly but come home and it messes up again. I had the Fiber Optics come out that I am with come out and they can’t fix either. I had another laptop before this one and thought it was the laptop, so I bought a new one, and same problem. Am I being parasite-ing off from a neighbor? The Fiber Optics company said it is not in the wiring and for me to call The Geek Squad, but they are $99.00 to walk in the door.

  17. computer deck top not responding I get a not responds recovery show I click it and go`s back to normal. I don`t know what to make of that. do you think it is bad or good!

  18. I am getting the nonresponse error message all the time. If I click on the X when the non response is happening I get a system crash. I) can I request from windows that they replace my existing windows program 2) It happens weather I am in IE or fire fox. I did uninstall fire fox and it helped some. 3) I get waves on screen all the time could that indicate a Hardware problem? 4) can the nonresponsive be caused by a slow running computer? I also have trouble when clicking on the X of getting no response.

  19. You mentioned a VB problem in your article. I’ve written a few programs that are fairly computationally intensive, and have occasionally gotten the “Not Responding” error for a few minutes. However, I’m working on a project now that has been running for approximately 12 hours displaying “Not Responding”. My question is this: is there a way to determine if the program is simply stuck on an intermediate process or if it is legitimately completing the task in an untimely manner? Some background on the situation: I’m running a machine with a Gen1 i7 eight-core and 20 GB of DDR3 RAM with the CPU priority for the program set to “High Priority”. The program is CPU-intensive, but not overly RAM-intensive. I made the rookie mistake of having it handle the entire data set at once with no intermediate checks or breaks, so the solution will need to be system-based, not program-based.

  20. Another thing that can cause an application to become non-responsive : Garbage collection.

    If the application, for any reason, do a lot of memory allocation and release, especially in a non-sequential fashion, the memory can become heavily fragmented. At some point, the garbage collection process kicks in in order to defragment and consolidate the RAM. This can take some time, even a lot of time.

    It’s becoming less of an issue with modern systems, but it can still happen.

  21. Color me confused! If a program uses some portion of memory and then releases it when whatever is completed the memory is still in the same place it was in when it was first used. I can see how data being used can be fragmented but not the space on the disk. Please if anybody responds to this use little words, computer whiz I am not.


    • Lets say you have 10 things located in memory. They’re all the same size, and they’re named A through J:


      Now you remove every other one:


      NOW you need to make room for something that’s twice as big — we’ll call it XX. There’s enough memory, but it’s not all together. Garbage collection is the process of moving things around so that there’ll be enough room:


      Now the XX can be added to the mix.


      Note: Not all memory allocation works this way, and not all of that that does does it efficiently. There are buckets of tradeoffs being made between performance at allocation time, release time, and garbage collection time. And yes, Garbage collection can sometimes take a lot of time, and when poorly implemented can appear as “Not Responding”.

      Finally: this isn’t about disk. This is about memory. RAM and DISK are two different things. :-)

  22. I was experiencing the “Not Responding” a lot lately in most applications. It would hang even accessing emails (I thought it was a DNS issue). The culprit? Ram. 80-85% used of 4 GB. I realized I had space for another 4 GB memory chip. Problem solved. I can’t wait to max out all that extra memory.

  23. Whenever I get a “Not Responding” (not often for me), eventually I’ll back away from the computer and go make a big fat sandwich. When I’ve been around other people, they’ll keep clicking their mouse on other things hoping for something to work. Those other clicks often do not help. Generally (but not always), all those other clicks get processed in the order they were clicked on, and they were clicked on AFTER whatever caused the original slowdown.

    • The clicks aren’t necessarily processed in the order they are clicked but if one program is taxing the system to the point of a “Not Responding”, running another program might make it take longer. I sometimes go into Task Manager and close down the “Not Responding” program and start it again.

  24. I have noticed that most of the “not responding” messages I get have to do with one major part of the system. ME! It’s called impatience.
    Occasionally, this will cause areas of the OS to enter a “race” state, where the area of the program can’t move to the next step until it completes the current one, but the current one is actually after the next one. If it’s hard to figure out what I just wrote, that’s part of the problem ( :) ). The solution to that is to leave the area for a minute or two, and let the OS catch up to me.
    Impatiently clicking on too many buttons in succession is one of the causes FOR ME.
    Looking back into my working years, one group I worked with was using the new DOS 5. We would come in in the morning, turn on the PC, go to the restroom, stop at the coffee station or water cooler, and by the time we got back to our cubicles, the PC would be ready to work.
    Then new hardware and software got faster! You could turn on the PC, and it would be ready to work in less than a minute.
    After a while, when many layers of security became necessary to protect the PC, things returned to the way they were when that other group used the DOS 5 OS.
    On the earlier comment about the VB program, I was taught that when one is working on a new program, one should build in pauses, report messages ( “I’m here now!” ), or input screens to allow the system to let one know where the program is in progression. Alter the program is running with no hangups, those can be removed.
    My current desktop is now telling me that it doesn’t have much available memory. But, I have a PC next to my desk that will solve that problem. All I have to do is set it up and start using it. ( :( )

  25. Browsers are some of the biggest memory hogs. For example, I have one tab open in Edge and Task Manager lists 25 instances and about 1 GB RAM use. Firefox with one tab open shows 13 instances and 1.3 GB RAM use. That seems to be what’s causing occasional “Not responding” errors. Is there anything on our end to reduce this? I’m going to try just using one browser open at a time so I’ll only have one browser trying to hog all that memory.

    • How many tabs in each?
      As you know I run several browsers. As I sit here I have open:

      • Brave – 1.7GB (primary browser)
      • Chrome – 0.85GB (the one I’m typing in)
      • Firefox – 0.66GB (idling)

      Other high memory usage is Dropbox, ~1GB (I have a huge dropbox), and Java runtime, used my a couple of apps I run, at 0.55GB, Everything else is under 1/2 a GB.
      There are 370 processes running on my machine, using a total of 27GB (out of 64 available). Yes, I run a lot of stuff.

      Look to see in Task Manager if your memory usage is maxed out. If not, then not-responding is likely coming from elsewhere.

      • As I mentioned in the comment, I only have only one tab open in each browser. In the Task Manager, the browsers show at the top of the list when sorted by RAM. They are usually over 1 GB RAM each. The total memory hovers between low and high 90% and likely it maxes out occasionally. I had already closed and disable Dropbox from starting with Windows. With no browsers open the total RAM was about 50% and the highest RAM user was thE Antimalware Service Executable at 98MB.


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