Numbers 3.0 won't save files!
Numbers 3.0 suddenly won't save files on my Macbook Pro.
I opened a .csv file, made some changes in Numbers, and tried to Save to my desktop. I get a window that says "The file '[filename].numbers' couldn't be opened".
I tried to Export to a .xls file, and also Share>Send a Copy>Email and chose Excel as the option. Same message about not being able to open the file.
This makes Numbers totally unusable for me. And for some reason, the old version of Numbers is suddly gone, so no fallback there anymore.
Any tips?
MacBook Pro (13-inch Late 2011), OS X Mavericks (10.9)