I have Elements 2018 as an upgrade, as I previously had Elements 10. Can I uninstall 2018 and re-install it without any problems? I have the serial number for 2018 but I'm concerned that once I uninstall 2018 I won't have any 'previous' version on my computer - a previous version is required in order to use an upgrade.
There is no software check for a previously-installed version of Adobe Photoshop Elements for you to be eligible for the upgrade pricing. Remember you don't actually pay for the application, you pay for a license to use the application, so the only check that is done by Adobe is that you have previously bought a license for an older version... you are an "exisiting user" in their eyes.