InDesign users have been facing this for a while now with versions CS5 and CS6. Crashes on exit, text disappearing when any is selected, font names disappearing from menus, and undos being limited to one or two, have become standard occurrences. Fortunately, these problems have fixes, though some may cost you.
Let's start with crashes on exit, a problem with InDesign CS5 (and Illustrator CS5 too). This is actually a new manifestation of a recurrent problem with Adobe apps: Adobe sets them to automatically access a server on the Internet that Adobe then eventually decommissions. The app can't access the missing server, so it crashes.
The solution is to stop InDesign CS5 from trying to access the server. The trick, though, is to do it permanently. You can find a number of methods on the Web involving deleting or renaming Adobe support files or cache files, but they only work till the app restores those files, which it does automatically.
Still, there's a simple way to do it. First, shut down InDesign CS5 and any other CS5 app. From your root drive -- not your User directory -- go to Library > Application Support > Adobe. (The Library directory is normally hidden, but you can reach it through the Finder's Go menu if you press the Option key.) Find the folder CS5ServiceManager and drag it to the trash.
Now, here's the important part. In a text editor like TextEdit or BBEdit, create an empty text file -- a file with no content. Name it "CS5ServiceManager" -- the same as the folder you trashed -- and move it to the same folder -- Library > Application Support > Adobe. With this empty file in place of its support folder, InDesign will no longer be able to attempt online access, and it won't crash again.
Why does this work while other prescribed fixes don't? Because when InDesign tries to overwrite your empty file with the proper folder of support files, MacOS won't let it. A file can overwrite a file, and a folder can overwrite a folder, but a folder is not allowed to overwrite a file!
OK, that deals with the crashes. But what about the other wonkiness? This seems to be due to obsolete memory handling in this fairly old software -- obsolescence that MacOS versions starting with El Capitan no longer accommodate. And no, increasing the memory on your computer won't help, as I learned from expensive experiment.
It took Adobe about a year to fix this for Creative Cloud customers -- which seems about typical for Adobe's lethargic customer support nowadays. But complaining owners of previous versions have regularly been told in forums that Adobe would NEVER fix it for them, because those versions are no longer supported. The only solution, supposedly, was to subscribe to Creative Cloud.
Fortunately, this was only half-true. Yes, InDesign CS5 is completely unsupported and will never be fixed. And yes, no new features are being added to InDesign CS6. But Adobe HAS supported InDesign CS6 to the extent of keeping it functional on later MacOS versions. So, when InDesign CC got its fix for these memory problems, so did InDesign CS6.
If you're having these problems with InDesign CS6, the simple solution is to go to InDesign's Help menu and check for updates. Sad to say, if you're using InDesign CS5, the only solution really is to update -- but if you don't want Creative Cloud, you can update to InDesign CS6 (then install its available updates.) Adobe itself has stopped selling it, though, so you'll have to find it elsewhere, new or used.
A quick note about moving from InDesign CS5 to CS6: I resisted this for a long time, because CS6 seemed much buggier. But most of that bugginess is now gone, and I appreciate this version's improved display of graphics. One big sticking point for me was CS6 opening document windows partially under panels. But it turned out I just had to select "Application Frame" from the Window menu to stop this.