I opened FreeFileSync and it installed the latest program version. When I went to run the backup of my OneDrive Personal Vault, I got the following error.
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Cannot set directory locks for the following folders:
Cannot write file "C:\Users\exact\OneDrive\Personal Vault\sync.ffs_lock".
Error code 0x1c0: The path cannot be traversed because it contains an untrusted mount point. [CreateFile]
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Ignoring the error also failed. Please help.
Onedrive folders outside my Personal Vault run just fine. My Personal Vault was unlocked when the backup was attempted.
OneDrive Personal Vault Failure
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- Joined: 4 Jul 2026
- Posts: 171
- Joined: 5 Jan 2024
Hi,
I duplicated your error and my research suggests that it cannot be done.
Microsoft treats that folder as a special type of folder and it doesn't adhere to normal file folder standards and free file sync cannot write its DB file.
The short answer is no, FreeFileSync cannot reliably back up or sync the OneDrive Personal Vault folder.
Even if you manually unlock the Personal Vault before running the backup, FreeFileSync will typically throw an error and fail.
Why It Fails
Microsoft deliberately isolates the Personal Vault from standard Windows file system operations for security. When you unlock the Vault, Windows mounts it as a specialized, restricted virtual drive (relying on BitLocker encryption behind the scenes).
When FreeFileSync attempts to scan or write to the Vault, it runs into two hard roadblocks:
* Lock File Failures: By default, FreeFileSync tries to write a temporary database file (sync.ffs_db) and a directory lock file (sync.ffs_lock) into the source and destination folders to track changes. Windows strictly blocks third-party applications from writing these database/lock files inside the Personal Vault directory structure. This triggers error messages like:
> “Cannot set directory locks... The path cannot be traversed because it contains an untrusted mount point.”
* Inactivity Timeouts: The Personal Vault automatically locks itself after a short period of inactivity (typically 20 minutes). If you have a large batch of files to back up, the Vault will often snap shut mid-sync, causing FreeFileSync to crash or log a string of critical read/write errors.
The Workarounds
If you need to back up the data trapped inside your Personal Vault using FreeFileSync or another sync tool, you have to bypass the Vault's mount point entirely:
* The Manual Route: Manually unlock the Vault, copy the files out of the Vault to a temporary, normal local folder on your PC, and then point FreeFileSync to that temporary folder.
* The Alternative Cloud Route: If you manage your own backups and value data sovereignty and encryption, consider shifting the files you want backed up into a standard local folder secured by a dedicated open-source utility like Rclone (with an encrypted remote), Kopia, or an encrypted container tool like VeraCrypt. FreeFileSync handles these virtual drives flawlessly, giving you the security of a vault without Microsoft's proprietary API restrictions.
I duplicated your error and my research suggests that it cannot be done.
Microsoft treats that folder as a special type of folder and it doesn't adhere to normal file folder standards and free file sync cannot write its DB file.
The short answer is no, FreeFileSync cannot reliably back up or sync the OneDrive Personal Vault folder.
Even if you manually unlock the Personal Vault before running the backup, FreeFileSync will typically throw an error and fail.
Why It Fails
Microsoft deliberately isolates the Personal Vault from standard Windows file system operations for security. When you unlock the Vault, Windows mounts it as a specialized, restricted virtual drive (relying on BitLocker encryption behind the scenes).
When FreeFileSync attempts to scan or write to the Vault, it runs into two hard roadblocks:
* Lock File Failures: By default, FreeFileSync tries to write a temporary database file (sync.ffs_db) and a directory lock file (sync.ffs_lock) into the source and destination folders to track changes. Windows strictly blocks third-party applications from writing these database/lock files inside the Personal Vault directory structure. This triggers error messages like:
> “Cannot set directory locks... The path cannot be traversed because it contains an untrusted mount point.”
* Inactivity Timeouts: The Personal Vault automatically locks itself after a short period of inactivity (typically 20 minutes). If you have a large batch of files to back up, the Vault will often snap shut mid-sync, causing FreeFileSync to crash or log a string of critical read/write errors.
The Workarounds
If you need to back up the data trapped inside your Personal Vault using FreeFileSync or another sync tool, you have to bypass the Vault's mount point entirely:
* The Manual Route: Manually unlock the Vault, copy the files out of the Vault to a temporary, normal local folder on your PC, and then point FreeFileSync to that temporary folder.
* The Alternative Cloud Route: If you manage your own backups and value data sovereignty and encryption, consider shifting the files you want backed up into a standard local folder secured by a dedicated open-source utility like Rclone (with an encrypted remote), Kopia, or an encrypted container tool like VeraCrypt. FreeFileSync handles these virtual drives flawlessly, giving you the security of a vault without Microsoft's proprietary API restrictions.
- Posts: 3
- Joined: 4 Jul 2026
I responded to the email but thought I should also respond on the forum in case others experience the same issue. I do love the product.
I reinstalled version 14.7 and the problem with backing up my Microsoft OneDrive Personal Vault was eliminated. The backups are running again. No problems.
I reinstalled version 14.7 and the problem with backing up my Microsoft OneDrive Personal Vault was eliminated. The backups are running again. No problems.
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- Joined: 8 May 2006
Does it continue to work in with the current release, 14.10 ?
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- Joined: 4 Jul 2026
No. That was the version that knocked out the OneDrive Personal Vault backup. I had updated from 14.7 to 14.8 with no problem. I am unsure if I ever updated to 14.9. What I do know, as soon as I updated to 14.10 the backups ceased to work.
I had my original 14.7 installation pack saved so I reinstalled and the problem disappeared.
I had my original 14.7 installation pack saved so I reinstalled and the problem disappeared.
- Posts: 1
- Joined: 7 Jul 2026
I have the same issue with two symbolic links within one of my sync folders since updating to 14.10, one pointing to a file on my OneDrive, and the other one to a folder in Users/Public/Documents. It's possible that others are affected in different sync folders, but I haven't checked. Though there are no other symbolic links in this particular folder. The configuration is set to follow them.
I went back to 14.9, everything works again, as it did before.
I went back to 14.9, everything works again, as it did before.
