WTH Homeassistant keeps crashing when making any changes

Dear Community, for a week now I experience strange behaviour with Homeassistant.

Visiting the webUI i can turn on and turn off lights and sockets via the Lovelace. However, whenever i try making a change Homeassistant crashes and reloads. For example when turning off an automation or even when just clicking „Yes“ to the question „Do you want to stay logged in?“ when loggin in with another device.

It seems that Homeassistant can not write anything to the disk or ram.

Does anyone know a fix?

PS: Sorry if this is the wrong category. I did not found one with problems and help.