"Not recognized" is not a diagnosis. Windows uses that sentence for about six different situations, and only one of them is a dead drive.

If somebody has already looked at your machine and told you the drive is damaged, they may well be right. But the checks below cost nothing, and I have been handed drives called damaged that turned out to be none of the above.

It often happens right after an update, and that is a clue.

Windows updates change storage drivers. Occasionally they change how the computer talks to the drive entirely. When a drive disappears the same week the machine updated, the update is usually involved, and that is good news rather than bad.

The cheap causes, in the order I check them.

The controller mode changed. There is a setting in the computer's firmware that decides how it addresses the drive. AHCI, RAID, IDE. If the machine boots one way and the drive expects another, the drive is physically fine and completely invisible. Flipping it back is a thirty second job.

The drive lost its letter. Windows assigns each drive a letter. Now and then it stops assigning one. The drive is healthy, spinning, and full of your files, and there is simply no D: for you to click.

A cable came loose. Inside a desktop this is common, especially after anything has been moved or opened. Both the data cable and the power cable are easy to seat almost all the way.

The driver rolled forward badly. The update installed, the storage driver did not take properly, and the machine came back without the drive.

The enclosure failed, not the drive. That is the whole of tomorrow's post.

The drive actually failed. This is the one everybody jumps to and it is the last one I check.

Where you can look without breaking anything.

Two places, both safe, both read only if you do nothing but look.

Right click the Start button and open Disk Management. This shows every drive attached to the computer, whether or not Windows gave it a letter. Then open Device Manager and look under Disk drives.

If the drive appears in either of those lists at all, it is alive. The computer can see it and talk to it. That rules out most of the bad outcomes in one glance.

A drive that shows up in Disk Management with no letter next to it is the best result on this page. It means the drive is fine and Windows simply has not given it a name.

Now the part that costs people their files.

Do not let anything repair the drive.

Windows will offer. It will suggest scanning and fixing. A pop up will tell you the disk needs formatting and ask if you would like to format it now. Recovery software will offer to rebuild the partition.

Every one of those writes to the drive. On a drive that is failing, writing is the worst thing you can do, because it spends the drive's remaining reads and can overwrite the very thing you are trying to get back. Say no. Say no to the format prompt in particular. It is the single most expensive click in this whole business.

Same for chkdsk. It is a useful tool on a healthy drive and a bad idea on a sick one.

What to do instead.

If the drive shows up and you can see your files, copy them off now, before anything else, before any repair. Copy the things you cannot replace first. Photos, tax records, anything work related. Then worry about the machine.

If the drive does not show up in either list, stop. That is the point where more attempts stop helping.

Bring the drive and the computer both. I need to see them together to tell which of the six it is, and five of the six are quick.

Tomorrow: why the box the drive lives in fails more often than the drive.