First, don’t format the drive.
Formatting will erase whatever’s on the hard drive, or at minimum, make it extremely difficult to recover your data.
I do have some suggestions of next steps to take instead.
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- “Unformatted” means critical information could not be read.
- Rule out hardware issues by trying other hardware — both computer and enclosure, if needed.
- Data recovery tools might help if the hardware all seems to be working.
- Backing up would have made this a non-issue.
When the system indicates that a drive is unformatted, it’s the result of attempting to read the master boot record, partition table, or other overhead information on the drive and getting something other than the expected data back.
In most cases, this is the result of the data on the disk somehow having been overwritten or otherwise damaged.
Less commonly, it can also be the result of a hardware failure, either in the disk itself or the circuitry connecting that disk to your computer.
Hardware problems are easiest to rule out.
Try another machine
If you have another computer available, plug the external drive into that and see if it is properly recognized.
If it is, then:
- You have access to your data (back it up now!).
- You know there’s an issue with the first computer that needs to be addressed.
Verify that external enclosure
Because you indicated that you placed your formerly internal drive into an external enclosure, I’m suspicious that there’s a problem with the assembly.
A working USB interface improperly connected to a hard drive could appear as an unformatted drive.
I’d make absolutely certain that the drive was properly connected to the interface card in that external enclosure. Double- and triple-check that all of the assembly instructions were followed and that the drive is attached correctly.
If you have another hard disk that you know to be functioning correctly, I’d be tempted to place that in the enclosure and try it. If it works, then you know you have a problem with the actual hard disk (which we’ll look into next). If it fails, then you know there’s either a problem with the enclosure itself, its circuitry, or the connection to your PC.
If everything seems to be connected and working properly, but your drive still shows as “unformatted”, it’s time to haul out data recovery software.
Piriform (the company that makes CCleaner) also puts out a free tool called Recuva. Among other features, they state, “Even if you’ve formatted a drive so that it looks blank, Recuva can still find your files on it.”
Naturally, no one can guarantee complete recovery, but it’s a place to start.
Another tool to consider is GetDataBack. It’s not free, but the free demo version should allow you to determine if the utility will be able to recover anything. If so, the tool might be well worth it. From their feature list: “GetDataBack will recover your data if the hard drive’s partition table, boot record, FAT/MFT or root directory are lost or damaged …”
This all would be moot if…
I’d be remiss in my job if I didn’t point out that none of this would matter — or at least it wouldn’t matter nearly as much — if you had a backup of the contents of that drive.
Remember the rule of thumb: if it’s only in one place, it’s not backed up.
Hard drives do fail, and often without warning. That can result in complete data loss.
Whether or not you recover your data this time, resolve to put a backup strategy into place so that the next time that there’s an issue (and please trust me, there will be a next time) the solution is simple: just restore your most recent backup.