I'm running the latest (20.04.1) version of Kdenlive under Windows 8.1. I am really interested in using the custom project settings to create square videos, but unfortunately these settings crash Kdenlive before I can even begin editing!
Here is what happens:

Start kdenlive with a blank HD 1080p 29.97 fps project loaded by default
Go to Project Settings from the Project Menu
Select Custom drop down menu
Choose Square 1080p 30fps or 60fps
Confirm Profile Change dialogue box
Kdenlive stops working

Please confirm and report this as a bug to developers.

Ok i canfirm that, openend an issue: https://invent.kde.org/multimedia/kdenlive/-/issues/724

my work-aorund is to load a clip before changing the project setting to a squared 1080

OK thanks for the issue creation.
You mean load any clip, regardless of the resolution (ex. Full HD) and then change the project settings?

yep.. i just placed a 1920x1080 clip on project bin .. and after that i changed the resolution to squared (i think that any clip is valid.. also .. squared clips)

P.S. i have not accepted the resolution change when asked... (i think this is not so important)
when changed to square.. Kdenlive asked me to save the project.. i saved it... and the squared layout is OK

BTW i think that the best way is to CREATE A NEW PROJECT FROM SCRATCH WITH CUSTOM SQUARED RESOLUTION.

I can't do that ... Going File->New and then choosing Square 1080p from the Custom also causes the crash.

Just tried with latest build... and i can select squares layout on Windows 10...
https://binary-factory.kde.org/job/Kden ... 64-gcc.exe