Issue Opening OneDrive Vault - Solution

Recently I have an issue where my OneDrive "Vault" is not opening.

This is the error I was getting:

It says "We couldn't unlock your Personal Vault", "We encountered an unexpected error and could not unlock your Personal Vault. Please try again. You can also access you Personal Vault on OneDrive.com".

As per error message, I couldn't open (Unlock) my OneDrive Vault on desktop (windows desktop app). Rest of the OneDrive was working fine, I could sync rest of the folder through desktop app without any issue. Online access also fine, and vault was opening on Online app. So it is clear, something was not ok on desktop app.

Unfortunately there were no error log on Event viewer or any other usual places.

Googled for solution, but couldn't find anything directly relate to this issue. Most issues were relate to OneDrive desktop app not being able to sync.

There fore, I have tried few things mentioned on those articles.

Unlink and Re-Link

First thing I tried was "Unlink" account from desktop app and re-add it. You can do this in Settings of the app in Account section (see below). However, note this will re-sync all your files. So if you have lot of files in your OneDrive prepare for long sync time.

Un-install and Re-Install

Second option was to un-install the OneDrive desktop app and re-install it.

You can un-install the OneDrive desktop app using the usual way you un-install any other app in windows.

Go to Settings > Apps > Installed Apps and un-install the app. Once completely un-installed, re-start the machine and install it by downloading the setup file (here is a link to OneDrive releases).

Un-block Network

Then you got to try un-block your network connection, in case there are something blocking the authentication to "Vault". For example, try disabling firewall and test (make sure to re-enable it again if it didn't work, if it work you will have to find which port/application getting blocked by the firewall).

Another advice is to try disabling anti-virus software and test. Again make sure to re-enable it again.

Make sure proxies or vpn you connected are not blocking the OneDrive.

For me none of these worked. So my final option was to contact Microsoft Support (I'm a paid Office 365 customer, so I'm able to get support from them).

First few letters from Microsoft support was not very useful as I have already done basic things which I covered above.

Clear Credential Cache

Next what Microsoft has suggested is following:

1. Press the Windows key  + R to open a "Run" dialog.
2. Enter the path %localappdata%\Microsoft\OneDrive\settings and select OK.
3. Delete the PreSignInSettingsConfig.json file.
4. Restart the machine

They said this would clear the credential cache.

But for me it didn't really work.

Bypass the Issue

Ultimately they have acknowledge that the problem I'm facing is part of ongoing issue, which their Engineering team is trying to resolve.

Until fix is implemented they have suggested below steps:

1. Exit the OneDrive desktop app.
2. Open command line via start menu and run the command- REG DELETE HKCU\Software\Microsoft\OneDrive\Accounts\Personal /v VaultBackupGuid
1. Its Ok if it returns Error: The system was unable to find the specified registry key or value.
3. Open credentials manager via start menu.
4. Select the Windows credential tab.
5. Find the credential named “Microsoft OneDrive Generic Data- Personal vault VHD info” and click Remove.
6. Restart OneDrive and then try to unlock the vault. 

This has actually fixed my issue.

Hope this will help someone going through the same issue.