I fixed it. For anyone else who encounters this issue here is the solution and full investigation detail.
TL;DR
If File History will not turn on (you press turn on from Control Panel/File History UI, it darkens as if it is about to start but then resets), check this value:
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Notifications\Data\41960B29A3BC1475
Command to check:
reg query "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Notifications\Data" /v 41960B29A3BC1475
If it is missing, restore it as:
REG_BINARY 0100000001000000
Command to restore:
reg add "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Notifications\Data" /v 41960B29A3BC1475 /t REG_BINARY /d
0100000001000000 /f
Then reboot.
On a separate healthy VM I deleted only this value and File History failed. Restoring only this value and rebooting made File History work again. The same fix worked on the original broken machine.
Full Investigation Detail:
I investigated a Windows File History failure where clicking Turn on did not complete. The root cause turned out to be a missing persisted registry value under:
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Notifications\Data
The specific missing value on the broken machine was:
41960B29A3BC1475
On healthy systems, it existed as:
REG_BINARY 0100000001000000
What the failure looked like
On the broken machine:
- File History would not enable successfully.
- fhsvc ended up stopped again.
- The healthy file set was not completed.
- The broken fingerprint was:
- local Catalog1.edb
- local Catalog1.jfm
- no Catalog2.edb
- no completed Config XML set on the backup drive
Advanced tracing showed the immediate failure path was:
- fhcfg!CDpConfigMgr::CreateCatalogs
- fhcat!DataProtectionCatalog::CreateStringTable
- ESENT!JetCreateTableColumnIndexW
- ESENT error:
- -621
- JET_errEngineFormatVersionParamTooLowForRequestedFeature
- translated back to:
- 0x800405ff
That HRESULT propagated back through fhcfg to the File History Control Panel enable path, which simply failed the Turn on operation without exposing a useful user-visible error code.
The fix
Restore this value:
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Notifications\Data\41960B29A3BC1475
REG_BINARY 0100000001000000
Command:
reg add "HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Notifications\Data" /v 41960B29A3BC1475 /t REG_BINARY /d
0100000001000000 /f
Then reboot and test File History again.
Why I am confident this is causal
This is not just correlation on one machine.
Broken machine before fix
- 41960B29A3BC1475 was missing
- File History failed
Broken machine after fix
- restoring only 41960B29A3BC1475 = 0100000001000000
- File History worked again
- fix survived reboot and clean reset/re-enable testing
Healthy comparison systems
Both a healthy Elitebook and a healthy VM had: 41960B29A3BC1475 = 0100000001000000 41960B29A3BC0C75 = 0100000001000000 and File History worked on both.Cross-machine repro on the healthy VM
I then tested the healthy VM directly:- deleted only:
- 41960B29A3BC1475
- left:
- 41960B29A3BC0C75 unchanged
- rebooted
- File History failed
- local result matched the broken pattern:
- only Catalog1.edb
- only Catalog1.jfm
- fhsvc stopped
- restored only:
- 41960B29A3BC1475 = 0100000001000000
- rebooted
- File History worked again
Safe scope
This is not a generic Windows tweak. I would only apply this fix if your machine matches the same pattern: - File History fails to turn on
- HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Notifications\Data\41960B29A3BC1475 is missing
- you see the same partial local catalog behavior
Likely origin
I do not have proof of the exact Microsoft-internal component that should have recreated this value, but current evidence points toward stale setup/rollback maintenance state rather than an ordinary File History UI problem. Static analysis made SetupCleanupTask.dll the strongest upstream policy-owner candidate. It contains explicit uninstall- window decision logic sourcing from: - CSP
- Registry
- OneSettings
- OOBE completion
- uninstall validity
- deployment in progress