Opera - Can't open user profile directory

I got the following ominous sounding message as I was about to fire up my Opera browser at the office today:

I don’t believe I’ve seen this one before. However, when running the application from the terminal the output made a lot more sense:

ERROR:process_singleton_posix.cc(1025)] Failed to create socket directory.
ERROR:opera_browser_main_parts.cc(1312)] Failed to create a ProcessSingleton for your profile directory.

I guess compiling that latest version of LibreOffice really did a number on my root partition. A quick look at the file system disk space usage confirmed the problem.

Filesystem  Size  Used Avail Use%  Mounted on
/dev/root   33G   32G     0  100%  /

After deleting a few GB of temporary files, Opera started up without further complaints. Simple fixes are the best fixes ;-)