Why am I getting a 'Couldn't start Dropbox' permission error?

This often happens with users who may have migrated old data and settings from another Mac to their current computer.

Operating system permissions prevent files from being viewed or edited by unauthorized logins. Permissions can be set any number of ways and can be restored manually through a fairly simple process. Please note that it is very important to follow these steps specifically as failure to do so may result in other issues. On a Mac OS X you can do the following:

1) Make sure the Dropbox desktop application is running

2) Click on the Dropbox icon in your menu bar and then click your profile picture or initials

3) Select 'Preferences'

4) Click on the 'Account' tab

5) Hold down the 'Option/Alt' key

6) Click on the 'Fix Permissions' button (make sure you're still holding down the 'Option' key.

This will allow Dropbox access to your home folder, Dropbox folder, and any required settings.