After an upgrade you may be unable to Synchronize CAD Download Formats and see an error message in case the WebCenter CADX service was not started (properly).
Symptoms
When trying to Synchronize formats in ADMIN > CAD > CAD Download Formats, you see the following error message (or similar):
Solution
To resolve this issue, restart the WebCenter CADX service on the Application Server.
Restarting CADX does not disrupt production, it will only disrupt the upload of CAD Documents (already not possible in this situation).