how to uninstall iTunes then reinstall on iMac OS X El Capitan v 10.11.6

Wait, it could be nothing to do with the application itself. Realize too the link Poikkeus1 provided dates to 2009 and back to a time when iTunes was considered a stand-alone application and not part of the system software the way it is today. Also I presume you want to have iTunes on your computer and the link only talks about uninstalling it.

Generally it is a good idea to make sure all the system software is up to date on the computer by running Software Update but if iTunes has been working up to this point and you have not made other major software changes you can try testing as things are.

First, try simply restarting your computer. If that does not help -->

Hold down the option/alt key while starting iTunes and create a new, test library. If iTunes starts, your old library file is corrupt and will need to be replaced from a backup or rebuilt from scratch:

ASC user turingtest2 help document: Empty/corrupt iTunes library after upgrade/crash - https://discussions.apple.com/docs/DOC-6561

If you don't see your content after updating iTunes - https://support.apple.com/kb/HT203225

If the option key method does not work -->

iTunes: Troubleshooting issues with third-party iTunes plug-ins - https://support.apple.com/HT203395 - hold down the Option/Alt and Command keys (on Mac OS X)

How to test an issue in another user account on your Mac - https://support.apple.com/HT204443 - "You can log in as another user to figure out if unexpected behavior is related to a specific user's settings or files."

Linc Davis Feb. 2016 - https://discussions.apple.com/thread/7456437?answerId=29767369022#29767369022 - remove corrupt preferences files

You can also try disabling or logging out and then back into various features such as iCloud services and Genius to see if the crash is resulting from their activity. E.g., https://discussions.apple.com/thread/7728841, https://discussions.apple.com/thread/7728668?answerId=30889815022#30889815022

If you cannot narrow the issue to being user-specific file problems you may need to reinstall iTunes:

- Apr. 2015 Niel post: Re-install iTunes application - https://discussions.apple.com/thread/6990002?answerId=28055467022#28055467022 - delete the old application first, with instructions on how to do that.

- April 2015 LincDavis post with a bit more detail on the method Niel outlines - https://discussions.apple.com/thread/7002727?answerId=28101611022#28101611022