How to Fix Credential Manager Error 0x80090345

Many users have reported issues with workstations that were previously connected to a domain. These workstations are not accepting Outlook credentials, and the Credential Manager refuses to start, displaying an error code 0x80090345.

The issue appears to be related to Windows updates KB3000850 and KB299261. We will try to resolve the issue without uninstalling the updates, and if that doesn’t help, we’ll uninstall the updates as it seems to be a sure workaround for this issue.

Solution 1: Set the value of the ProtectionPolicy registry entry to enable local backup of the MasterKey

To address this problem we need to edit a registry entry to enable local backup of the MasterKey instead of requiring a RWDC. To do this:

1. Hold down Windows key + R to bring up the run dialogue box
2. Type regedit and press Enter. If you get a UAC prompt, click OK and proceed
3. In the left navigation pane, locate and click HKEY_LOCAL_MACHINE
4. Open the next subfolder named SOFTWARE
5. Afterwards, locate the Microsoft folder and open Cryptography under that.
6. Under the ‘Cryptography‘ folder, you will find the ‘Protect‘ folder and the ‘Providers‘ subfolder within it.
7. Locate df9d8cd0-1501-11d1-8c7a-00c04fc297eb under Providers
8. After selecting df9d8cd0-1501-11d1-8c7a-00c04fc297eb, look for ProtectionPolicy on the right side. If it doesn’t exist, then create the DWORD 32-bit value and name it ProtectionPolicy.
9. Double click on ProtectionPolicy and change the registry entry value to 1.

Solution 2: Uninstalling the updates KB2992611 and KB3000850

Since the problem revolves around the Microsoft updates KB2992611 and KB3000850, if Solution 1 does not help, we can uninstall these updates and prevent them from being reinstalled automatically. The following steps instruct us on how to proceed with the process:

1. Press the Windows Logo key + X to open the advanced menu in the lower-left corner of the screen
2. Go to Programs and Features and click on View installed updates on the top left corner
3. Look for KB2992611 in the list or by typing KB2992611 in the search box at the top right corner
4. Right click on the update and select Uninstall
5. Repeat the same steps for KB3000850
6. Restart the computer
7. Download and run the Show or hide updates troubleshooter for Windows 10 from Microsoft.
8. When you run this troubleshooter, it will search for available updates and give you an option to “hide” them, preventing the updates from automatically installing.