The short answer is yes, but no.
Yes, you can delete partitions, but no, I would not advise it. As you say, you don’t know what the partitions are, so you don’t know whether or not they’re needed. It’d be a shame to delete one and find out later that this was a serious mistake.
However, if you feel the need, I do have one approach to doing it more or less safely.
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Why so many partitions?
Newer machines frequently come with Windows 10 installed and the primary hard disk partitioned into as many as five separate partitions.
This leaves many people asking: why? Why all those partitions when a single partition did the job in the past?
It’s the result of several changes over the years, including UEFI, the disappearance of installation media, and more.
What are those partitions?
Using one of my machines, an original Microsoft Surface tablet, as example, we see the following partitions:
- Recovery Partition (600MB)
- EFI System (200MB)
- C: (110GB)
- Recovery Partition (450MB)
- Recovery Partition (7.8GB)
The EFI partition is required by UEFI/GPT formatted hard drives. It’s what the machine boots into when first started. Confusingly, this is often referred to as the “System” partition, even though it’s not the system you and I might think of.
The C: partition is obvious: that’s the hard disk you see and use when you’re running Windows. This is what I tend to think of as the “system” partition or drive, since it contains my system (Windows), as well as all my applications and data. It’s by far the largest partition on the drive.
The three recovery partitions are more of a conundrum. I theorize that the larger one, at 7.81 gigabytes, contains a pristine copy of Windows 10 and takes the place of physical installation media. The other two I suspect are recovery consoles containing the recovery environment, tools, and other recovery options.
I also suspect that recovery partitions are extremely manufacturer-dependent. What I see on my machine will be different than what you see on yours. Even the content of these partitions varies dramatically based on the decisions made by your computer’s manufacturer.
My advice: leave well enough alone
If you want to remove partitions, it’s important to realize that you’re trading off the reasons for the layout — whatever those reasons were — for a small increase in disk space.
My example machine above is already fairly old, with a comparatively small hard disk. Even if I did delete all the partitions other than the required EFI partition and the C: partition, I’d be recovering only 8.5GB at best, an increase of less than 8%.
Given that today’s hard drives are larger while the sizes of the reserved partitions haven’t increased proportionately, you’re likely to get even less of an increase.
In my mind, it just isn’t worth it. I’d much prefer to have the recovery options available to me should I ever need them.
If you must: create a safety net
There is one way to do this safely, of course.
Start with a complete image backup of the entire hard drive. Make sure all partitions are included. Save that backup somewhere. (If you’re backing up regularly, as you should be, you may already have this. If you’re at all uncertain, make another backup.)
Then delete the partitions. If you’re going this far, I’d be tempted to delete all the “recovery” partitions with the knowledge that should your system need recovery, you’ll need to do it some other way. Typically, that means booting from a manufacturer-supplied recovery disc, system disc, or USB stick, or restoring the backed-up system from the previous step to perform a recovery.
Merging the freed-up space can be as simple as using Windows’ own built-in disk manager, or it may require a partition-management tool to combine the freed-up space.
- Can I Make My C: Partition Bigger by Taking Space from D:? – Changing the layout of the hard disk to make the C: partition bigger requires a few steps and occasionally special tools.
- Should I Partition My Hard Disk? – Partitioning, or splitting a single physical hard drive into multiple logical drives, has pros and cons. I’ll look at those and make a recommendation.
- How Do I Remove the Recovery Partition on My Machine? – If you’re doing backups properly, recovery partitions can become redundant. I’ll look at how to remove a recovery partition and reclaim the space.