SSD or Hard Drive Disappeared After Windows 11 Update KB5063878: How to Fix It

What Is Causing SSDs to Disappear After the Windows 11 KB5063878 Update?

Windows 11 update KB5063878, released for version 24H2, contains a bug making some SSDs and hard drives vanish from Windows during large, sustained write operations. Drives around 60 percent full or more are hit hardest. The drive stops responding, drops out of File Explorer, and in some cases disappears from Disk Management too.

The trigger pattern reported by affected users is consistent: copying, installing, or downloading roughly 50GB or more of data in one continuous write session. Game installs, large video file transfers, and backup jobs all match this profile. A drive running fine for months drops out mid-transfer with no warning beyond a stuck copy dialog or a sudden "This device is not connected" message from File Explorer.

Microsoft has acknowledged reports tied to this update. Until a permanent fix ships, the safest move is to stop writing to the affected drive immediately if you see symptoms, and follow the recovery steps below in order.

What Should I Do the Moment I Notice My Drive Is Missing?

Stop any copy or install job still running, then check whether the drive still responds before you touch anything else. Do not format, initialize, or repartition the drive if Windows offers to, even if it looks like the fastest fix.

Follow this order:

• Cancel any file transfer or installation still in progress on the drive.
• Do not restart the PC yet. A reboot sometimes brings the drive back on its own, but it also risks making a marginal drive drop out for good.
• If File Explorer still shows the drive and lets you open it, copy your most important files to a different drive right away.
• If the drive is gone from File Explorer, open Disk Management before deciding on next steps.

Formatting or initializing a drive Windows suddenly treats as "new" or "unallocated" wipes the partition table. If your files sit physically on the disk still, this step erases the map to find them, even though the raw data stays recoverable at this point in many cases.

How Do I Check Disk Management for the Missing Drive?

Open Disk Management by right-clicking the Start button and choosing Disk Management, or by pressing Windows key + R, typing diskmgmt.msc, and pressing Enter. Look at the bottom pane for a disk showing the correct capacity but no drive letter, or one labeled "Unallocated."

Three outcomes are common:

• The disk shows up with its correct size but no letter assigned. This is the easiest case. Right-click the volume, choose "Change Drive Letter and Paths," click Add, and assign an unused letter. Your files should reappear in File Explorer under the new letter.
• The disk shows as "Unallocated" space with the correct total capacity. The partition table has damage, not the data itself. Do not click "New Simple Volume" yet; this action creates a fresh partition and overwrites the pointers to your existing files. Instead, close Disk Management and run a partition-recovery tool such as TestDisk, or hand the drive to a data recovery service, before creating anything new.
• The disk does not appear in Disk Management at all. Software-level recovery won't help here. The controller on the drive itself fails to respond to Windows. Skip to the section below on drives missing everywhere.

How Do I Uninstall KB5063878 to Stop the Bug From Recurring?

Go to Settings > Windows Update > Update History > Uninstall updates, find KB5063878 in the list, and click Uninstall next to it. This removes the specific patch without rolling back your entire Windows version.

After uninstalling, Windows will likely try to reinstall the same update automatically on its next check. To buy time until Microsoft ships a fix, pause updates for a few weeks: go to Settings > Windows Update and use the "Pause updates" option, choosing the longest available window. Check Microsoft's release health dashboard periodically for a note confirming the SSD issue has a permanent resolution before you let updates resume normally.

Uninstalling the update does not repair a drive already dropped out. Treat it as prevention for the future, not a fix for a drive problem you already have. Handle the missing drive with the Disk Management steps above first, then uninstall the update to stop it from happening again.

What If the Drive Doesn't Show Up in the BIOS or UEFI Either?

If your drive is missing from Disk Management, restart the PC and check the BIOS or UEFI setup screen (usually by pressing F2, F10, F12, or Delete during boot, depending on your motherboard). If the drive is missing there too, the controller has stopped responding at the hardware level, and no software running inside Windows fixes this.

At this point, your options are:

• Send the drive to a professional data recovery service if the files on it matter enough to justify the cost. These services work directly with the drive's raw memory chips and do not depend on Windows recognizing the drive first.
• Replace the drive if the data was backed up elsewhere or wasn't critical.
• Contact the drive manufacturer's support line. Some SSD makers have issued their own firmware or diagnostic tools in response to this exact Windows update problem, and a few have extended warranty support for drives lost during the affected window.

How Do I Avoid This Happening Again?

Back up anything irreplaceable, and break up large file operations into smaller chunks until Microsoft confirms a fix. A single 200GB transfer is exactly the kind of job triggering this bug; four 50GB transfers with a short pause between each one form a safer pattern based on current reports.

Other steps worth taking now:

• Check Settings > Windows Update > Windows Update history to confirm whether KB5063878 is already installed on your machine.
• If it isn't installed yet, pause updates before your next large file job, particularly if you regularly move game installs, video footage, or backup archives near the 50GB mark or higher.
• Keep drives below 60 percent full where practical. Reports tie the bug to fuller drives more consistently than nearly empty ones.
• Run a current backup of anything irreplaceable to a second physical drive or a cloud service, independent of whether you've hit this bug yet.

None of these steps guarantee a fuller drive won't drop out. They lower the odds while you wait for Microsoft's fix, and they protect your files regardless of whether this specific bug ends up being the one causing a problem.

Frequently Asked Questions

Will uninstalling KB5063878 bring my SSD back automatically?

No. Uninstalling the update stops the bug from triggering again on future large transfers, but it does not restore a drive already dropped out. Check Disk Management first and reassign a drive letter, or run recovery software if the drive shows as unallocated or missing entirely.

Is it safe to keep using my SSD while I wait for a permanent fix?

Back up your data first, then avoid single continuous file transfers larger than 50GB until Microsoft ships a permanent fix. Smaller transfers with pauses between them have not been reported to trigger the bug.