How to clear the Lync or Teams cache

Microsoft Skype for Business and Teams caches files locally on your computer. This may prevent you from being able to sign in to Skype for Business.

If you suspect that this issue is affecting you, try the following method:

1. Sign out of the Skype for Business or Teams client.
2. Delete all cached sign-in credentials.
3. Sign in to Skype for Business or Teams again.

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Manually clear the cached information.

To manually fix this issue, follow these steps.

Step 1. Clear your Skype for Business cache

1. Click the gear icon in the upper-right corner of the Skype for Business client, click File menu, and then click Sign Out.

2. Click Delete my sign-in info.

   

3. Locate your local AppData folder:

   • If you're using Skype for Business 2016, the folder is located here: %LOCALAPPDATA%\Microsoft\Office\16.0\Lync
   • If you are using Skype for Business 2013, the folder is located here: %LOCALAPPDATA%\Microsoft\Office\15.0\Lync

4. Delete the folders that contain your sign-in information. The folder name resembles sip_user@contoso.com.

5. Delete all files in the Tracing folder.

6. Sign in to Skype for Business again.

If you still cannot sign in, go to Step 2 to clear the registry keys.

Step 2: Clear the Skype for Business registry keys

1. Start Registry Editor. To do this, right-click Start, click Run, type regedit in the Open box, and then press OK.

2. Locate the following subkey:

   • If you are using Skype for Business 2016, locate: HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Lync
   • If you are using Skype for Business 2013, locate: HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Lync

3. Delete the folder has the name of your sip address. For example: user@contoso.com.

If the issue persists, go to Step 3 to remove the cache.

Step 3: Remove Skype for Business cache

1. Locate your local and roaming AppData folder:
   • If you are using Skype for Business 2016, locate the following subkey: %LOCALAPPDATA%\Microsoft\Office\16.0\Lync %userprofile%\appdata\roaming\Microsoft\Office\16.0\Lync
   • If you are using Skype for Business 2013, locate the following subkey: %LOCALAPPDATA%\Microsoft\Office\15.0\Lync %userprofile%\appdata\roaming\Microsoft\Office\15.0\Lync
2. Delete the folders that have the name of your sip address.
3. Delete the AccountProfiles.dat file.

Source:

https://docs.microsoft.com/en-us/skypeforbusiness/troubleshoot/server-sign-in/unable-to-sign-in-to-sfb