We identified that a recent update from a partner extension has been causing CET to crash upon startup or is causing drawings to crash when opened. We notified this partner extension and they were able to quickly push out a hotfix for this issue.

Here is how to apply this hotfix:

Scenario 1 - CET will not open -

1) Open the Windows File Explorer and navigate to C:\Users\%username%\Documents (you can paste this address directly into File Explorer)
2) Rename the "CET Documents" folder to another name, just remember what name you set this to:

3) Start CET and Check for Updates by going to Help > Check for Updates. Do not attempt to use CET at this point.

4) When prompted restart with updates, ensure there are no further updates for CET by going to Help > Check for Updates. Once you see the message that no updates available (like the image below), move on to step 5:

5) Return to C:\Users\%username%\Documents and delete the new "CET Documents" folder that was created.
6) Rename your original CET Documents folder back to the name "CET Documents". You should now have all of your settings back and be able to use CET again.

Scenario 2 - CET opens but all drawings crash - 
1) Start CET and Check for Updates by going to Help > Check for Updates. Do not attempt to use CET at this point.

2) When prompted restart with updates, ensure there are no further updates for CET by going to Help > Check for Updates. Allow CET to Restart once confirmed.