VM checkpoint restore fails with error 0x80042306

Quick answer

Run vssadmin list writers and check if any VSS writers show as "failed" or "stable with error". Restart the Volume Shadow Copy service if there's a problem. Also check the VM host's drive where the checkpoint files live has at least 20% free space.

Why this happens

This error shows up when you try to restore a VM from a checkpoint and Windows can't create a temporary shadow copy. The culprit is almost always a VSS writer that's gone sour after a failed backup or a disk that's too full for the shadow copy to expand. I see it most often after someone runs a backup job that leaves the VSS writers in a confused state. Another common trigger: the VM host's C: drive is under 10% free space — Hyper-V needs room for shadow copy diffs. People think it's a VM problem, but it's almost never the VM itself.

Fix steps

1. Check free disk space on the VM host's drives — especially the one holding the checkpoint files. You need at least 10% free, but I'd push for 20%. If low, move or delete old checkpoints and free up space. Then retry the restore.
2. Check VSS writers status. Open an admin command prompt and run: vssadmin list writers. Look for any writer with "Failed" or "Stable with error". If you see one, take note of its name.
3. Restart Volume Shadow Copy service. In Services.msc, find the service named "Volume Shadow Copy". Right-click and restart it. This will clear any hung writers. Then wait 30 seconds and run vssadmin list writers again — they should all show "Stable".
4. Retry the checkpoint restore from Hyper-V Manager. If it fails with the same error, move to the alternative fix below.

Alternative fix if the main one fails

Sometimes the VSS writers are stubborn. In that case, restart the entire host's Hyper-V management service. Run these commands as admin:
net stop vds
net stop hkmsvc
net start vds
net start hkmsvc
Then run vssadmin list writers and confirm all writers are stable. If this still doesn't work, you've got a corrupted VSS system. Run vssadmin delete shadows /all to wipe all shadow copies (this doesn't affect checkpoints — they're different), then retry. I've also seen cases where the VM's own VSS writers cause this — shut down the VM and use its saved state or checkpoint restore from Cold Migration. Don't bother with chkdsk or SFC — they rarely help here.

Prevention tip

Set up disk space alerts on the host. Any drive that stores checkpoint files should trigger a warning at 15% free space. Also schedule a weekly vssadmin list writers check in your monitoring tool. If a writer fails, restart the service before it causes restore failures. That little check saves me at least one ticket a month.