Jacques Bédard 
The issue you are currently facing is most likely caused by a set of corrupt user settings which prevent Studio to start; the fact that you're seeing the same problem after reverting to the previous version also points to that root cause.

Can you please navigate to this location on your machine:

C:\Users\%username%\AppData\Roaming\Trados\Trados Studio
(if you copy this above-mentioned path in Windows Explorer it should take you to that location)

and rename the "Studio" and "18" folders found there to "Studio _ old" and "18 _ old"

If this doesn't do the trick, navigate to the "Documents" folder on your machine and rename the "Studio 2024" folder found there to "Studio 2024 _ old".

I have also raised a Support Case on your behalf if the resolutions I provided here do not work \ Support Case Id : CS0020655.

If you've managed to resolve the issue though, please let us know so we can close the Case from our end; otherwise one of our Engineers will reach out to you.

Best Regards,
Vlad 

 Jacques Bédard 
The issue you are currently facing is most likely caused by a set of corrupt user settings which prevent Studio to start; the fact that you're seeing the same problem after reverting to the previous version also points to that root cause.

Can you please navigate to this location on your machine:

C:\Users\%username%\AppData\Roaming\Trados\Trados Studio
(if you copy this above-mentioned path in Windows Explorer it should take you to that location)

and rename the "Studio" and "18" folders found there to "Studio _ old" and "18 _ old"

If this doesn't do the trick, navigate to the "Documents" folder on your machine and rename the "Studio 2024" folder found there to "Studio 2024 _ old".

I have also raised a Support Case on your behalf if the resolutions I provided here do not work \ Support Case Id : CS0020655.

If you've managed to resolve the issue though, please let us know so we can close the Case from our end; otherwise one of our Engineers will reach out to you.

Best Regards,
Vlad