Yes, generally it is fine to delete all but the last installation directory. Here’s how it works. And you may as well delete them since (1) you can’t use them anymore once it’s updated, at least not without modifying the registry, and even then, your updated profile may no longer be compatible with the old versions (well, it is possible, but it requires digging into the profile and doing things that you really don’t want to do), and (2) updates are frequent enough that it becomes ridiculous to keep every single old version in perpetuity.
Each version is expanded into a separate directory named with the version. There is a
Dictionaries folder that contains the spell-checking dictionary (you want to keep that). There will likely be a
debug.log file that you can leave alone, and an empty
First Run file that simply tells Chrome if it’s been run yet (and whether or not to show you intro stuff). You may or may not also have a
master_preferences file that has some global preferences, and an
old_chrome.exe which is the executable from the last version.
What normally happens is that if Chrome successfully updates, then the new version is expanded to a new directory with that version as the filename, and the EXE is replaced with the one from the new version. So, open the Wrench->About dialog and check the version. You should have a directory corresponding to that, and then you can delete the other ones (the version ones, not Dictionaries or any others you may have). You can also delete
old_chrome.exe if you’ve got it (for some reason,
chrome.exe still doesn’t contain the right version in the resources :roll:). Leave the rest alone.
If you are hard-up for space, you can also delete the
Installer folder inside the one you keep (eg,
11.0.696.71\Installer). It contains the installation archive and program for that version which can run about 80MB. If it installed correctly and you’re running it without issue, then you probably won’t need to reinstall that version again.
As Moab said, if worst comes to worst and somehow Chrome dies for some reason (like if you accidentally delete the wrong thing), then you can reinstall the latest version anyway.