Launch Lightroom and go to the menu: Help >> Sign Out <your email address>
Re-launch Lightroom and click the button “Sign In Now”
Click the button “License This Software”
Enter serial number & click Next
Lightroom will launch as LR6
Thank You! I was just posting this;
Well, I redid my serial # & I have my Lightroom back.
Hopefully I won't have to do this each time I log back onto Lightroom.
Yes, it's in the Help tab. No need to use it unless you're uninstalling the software.