Animate 2021 Stops Responding when I Import Video

I do a lot of rotoscoping with Animate which means I always import a video into the timeline and animate over it. After updating to Animate 2021, every time I try to import a video Animate stops responding and will never fix itself/start responding again. The video I want to import is only 5 seconds long so file size shouldn't be an issue.

The steps I'm taking to import are:

File - Import - Import Video - Embed H.264 Video in Timeline

I then make the symbol type "Graphic" and uncheck "Include Audio".

After I click Finish, Animate stops responding. I've tried other combinations of the import settings but nothing is working. I know this should be possible because I used to do it all the time on the 2019 version. 

Any help would be much appreciated and if you need any more information concerning my settings or anything, I can provide it.