Logic can't find certain loops or samples

There are certain loops and samples(mostly in the EXS24 interface) that it can't find. When I click on the loop I get an error message saying "Can't find loop: Logic couldn't find the selected loop in the indexed location. Do you want to continue, or reindex your loops? If you have loops located on an external drive, make sure the drive is connected and click Continue to use the loops." and it gives me two options: "Reindex loops" or "Continue". Not sure what to do or what I need to do. I've clicked on "Reindex loops" however it doesn't fix anything. Also I know that the loops aren't located on an external drive.

For the sample libraries, an example of the message I get would say "EXS24 instrument '[name of sample]': Audio file “YTELEKT14X01.aif” not found!

This happens with quite a few of them. I'm not really sure where to look.

Should I uninstall and then reinstall? If so, how would I do a safe uninstall?