Ubuntu software center isn't opening!

Solution 1:

The issue is the snap-store is unable to load it's database for the first time. You need to remove then reinstall the snap:

sudo snap remove snap-store
sudo snap install snap-store

Solution 2:

I had the same issue on 20.10. Following a comment in this bug report, I was able to fix it by removing the pixbuf loaders cache at ~/snap/snap-store/common/.cache/gdk-pixbuf-loaders.cache.

I haven't had any of the subsequent issues that comment mentions, I'm assuming it's because I specifically removed the pixbuf-loaders cache and didn't wipe all the cache out like they did.