But now the system tells me that "it might be read only". The file upon right click says it has permission for read and write though, if I understood correctly.
What can I do to be able to save changes again?
"The changes location is not writable. This may be because the changes path is located on a read-only filesystem."

Solved: when I expanded the file, the system saved it as .dat.dat, which ends up being a different name on the config file