virt-manager freezing up when clicking Browse in any window

The title explains what the problem is. You might've also noticed that it spikes a CPU core's utilization to 100%. Furthermore everything works if you enter a file location manually in the corresponding input field, it's just that darn button.

This issue is caused by some sort of problem with the storage pools[1] when it tries to load them. I was able to fix it by pretty much deleting that folder, but you really should just rename it:

sudo mv /etc/libvirt/storage /etc/libvirt/storage-broken

libvirt automagically regenerates the original folder, so you might need to restart it:

sudo systemctl restart libvirtd

[1]The storage pool is just a folder with files that store what locations can be used by virtual machines (more info here). In the case of virt-manager, pretty much every time you select any folder or file, a folder entry gets added there. ^