Diagnostic finding
Drive wear and errors
This check reads the counters a drive keeps about its own health: how much of its rated write life is used, how long it has been powered on, and how many reads and writes it could not recover. It produces one of four messages.
Find the message your report showed
This check can produce four different messages. Each one has its own section below.
Unrecoverable read or write errors
The drive could not recover this data. Back up now and replace the drive. Running repairs against a drive in this state can make recovery harder.
The drive tried to read or write data and could not, even after its own internal retries. Some of what was stored in those places is gone.
What to do
- Stop saving new files to this drive.
- Copy the files you cannot replace to another drive or to cloud storage now, most important first. If a copy stops or freezes, skip that file and carry on with the rest.
- Do not run disk repair tools on this drive until the copy is done. That includes
chkdsk /fandchkdsk /r, which write to the drive while they work. - Replace the drive.
90 percent or more of rated write life used
Replace this drive. Copy anything irreplaceable off it first, and do that before any repair work, not after.
Solid state drives are rated for a limited amount of writing. This drive reports that it has done most of it. The figure can pass 100 percent; a drive does not stop working at that point, but it is past what its maker estimated.
What to do
- Confirm you have a current backup of this computer, and that it includes this drive.
- Copy anything you cannot replace off the drive.
- Replace the drive now rather than at the next convenient time.
80 to 89 percent of rated write life used
Plan to replace this drive. It is not failing yet, but it is past the point where a replacement should be scheduled rather than waited for.
There is nothing wrong with the drive today. The figure says it is approaching the end of the life its maker estimated, and a planned replacement is cheaper and calmer than an emergency one.
What to do
- Confirm you have a current backup of this computer, and that it includes this drive.
- Schedule the replacement. Run the scan again in a month to see how fast the figure is moving.
Drive wear could not be measured
These drives report no wear or error counters to Windows: DRIVE_NAMES. That is common on consumer SATA drives and on anything connected over USB. It means this check cannot warn about them, so their absence from the findings above is not a clean result. A drive that matters should be checked with the manufacturer's own tool.
This is information, not a fault. It does not mean the drive is failing, and it does not mean the drive is healthy. It means the measurement did not happen.
Drives in an external USB enclosure usually cannot pass these counters through to Windows at all, whatever the drive inside is.
What to do
- If nothing important is stored only on this drive, nothing is needed.
- If it matters, check it with the drive manufacturer's own utility, downloaded from the manufacturer's website.
What the check reads
Run in PowerShell opened as administrator. This lists the drives and their device numbers, and changes nothing.
Get-PhysicalDisk | Format-Table DeviceId, FriendlyName, MediaTypeThen read the counters for each device number. This also changes nothing.
Get-PhysicalDisk | Get-StorageReliabilityCounter | Format-List DeviceId, Wear, PowerOnHours, ReadErrorsUncorrected, WriteErrorsUncorrectedDeviceId : 0
Wear : 0
PowerOnHours :
ReadErrorsUncorrected :
WriteErrorsUncorrected :Wear 0 with the other three blank is the sign. A drive that does report counters shows a power-on hours figure beside its wear figure, even when the drive is new. When all four are blank or zero together, the drive is publishing nothing, and a wear of 0 means nothing.
What each value means
| Counter | What it tells you |
|---|---|
Wear | Percentage of the drive's rated write life used. At 100 the maker's estimated wear limit is reached. Solid state drives only. |
PowerOnHours | Hours the drive has been powered on since it was made. |
ReadErrorsUncorrected | Reads the drive could not correct. Any value above zero is a reason to act. |
WriteErrorsUncorrected | Writes the drive could not correct. Same rule. |
Counter definitions are Microsoft's, from the MSFT_StorageReliabilityCounter class reference, not ours.
What this page is based on
Observed or documented
- Microsoft documents Wear as a percentage, where 100 means the estimated wear limit has been reached.
- Drives that publish no counters return a wear of 0 with the other counters blank. We have seen this on real machines, including the boot drive of a working computer.
Our judgement
- The 80 and 90 percent points are where we recommend planning and then making a replacement. They are not manufacturer figures.
- That repair tools can make recovery harder on a drive with unrecoverable errors comes from bench work, not from a measured rate.
- We have no evidence that a drive publishing no counters is more likely to fail, and this page does not suggest it.
When this is worth a call
Call us if your report shows unrecoverable errors, if files will not copy off the drive, or if the computer freezes during large copies. A wear figure on its own can usually wait for a scheduled visit.
Reviewed November 4, 2026 · Applies to Windows 10 and Windows 11 · Finding storage.wear, wording from Connected Geek Diagnostic Tool 0.9.28