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 pools1 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. 

^