Sprite editor makes Unity freeze and I overcome this by selecting all assets in the project window then I get these messages:
Sprite editor also freeze on my linux mint, after window is show i cant click any button, nothing works. I decided use XML TextureAtlasSlicer as workaround.
I used to close Unity when this happen and it freezes, but I found if I pressed ctrl+a on the project windows it gives me some error message and continue working.
Can confirm, had the same issue in 2020.1.17f1, but no issues on 2019.4.17f1 LTS, for what it's worth. Running Ubuntu 18.04, can provide more system details if necessary.
Select the Tileset you want in your Sprite Editor and then go to Sprite Mode and set it to Multiply, Filter mode to Point(no filter), and Compression to none. It worked for me