[2021.4 - 0588 and 0595] Unhandled exeption on startup

Straight after installation of the RC, i get an unhandled exeption on startup (after showing the splash screen (compiling etc. took quite a bit)), click on Continue quits the application.

Exeption text: exeption_text.zip (153.3 KB)

2021-4_588_RC_Unhandled Exeption

Also tested with todays preview 0595 gettin the same problem.

2021.4.0.444 (last version i had installed before) and 2021.3.3 are running fine.

It’s an intel NUC i5-7260U @2.20GHz with Intel Iris Plus Graphics 640 (1GB)
Windows 10 Pro 10.0.19043

Screens attached:
1x 1920x1200 @72dpi (100%)
1x 1280x1024 @72dpi (100%)

hey benju,

on this PC, have you by any chance modified the theme? or are you using a custom theme?

can you check if it makes a difference if you delete the settings file (which will recreate a clean one):


if that doesn’t help: are there any nugets installed yet on this PC, see here:


Yes I was having my custom lessdark-theme in use.

I just tested it on another machine with the same custom theme without getting an exception, will give it a try back in studio (this may be end of the week though),

Yep. There were some nugets installed from older previews. Will clean it if the theme/settings solution did not help and report about the behaviour.

we were able to track this down to a non-existing .css file specified in settings. fixed for latest 2021.4 previews.

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