Reinstall Lightroom Classic

Exactly which version number?

As far as I know, version 6 requires the process below

Adobe removed old links from public view https://theblog.adobe.com/changes-to-creative-cloud-download-availability

-also read https://prodesigntools.com/adobe-limits-software-downloads.html

IMPORTANT NOTE:

The process below WILL NOT WORK if you have a (CS6 or earlier) serial number for an education or volume version, since the only downloads now available are the retail installers, which DO NOT work with an education or volume serial number

Start by reading reply #10 https://forums.adobe.com/thread/2620448

-Also read https://helpx.adobe.com/in/download-install/kb/downloaded-older-app.html

-And https://helpx.adobe.com/x-productkb/global/find-downloaded-file-app.html

-OR... Go to https://www.adobe.com/about-adobe/contact.html

-click on the Chat bot on the bottom right hand corner of the first screen

--the chat bot is the circle with a funny looking box with 3 dots inside

-click on Downloading or Installing, then type Agent

Do NOT let the support agent tell you to come to the forums for help... no user in a public forum has access to Adobe's internal links, you MUST obtain the program and update links from Adobe support

AND when you finally do have a download link, be sure to copy every file you download to an external drive (or 2 or 3) so you never have to hunt for download links if they are moved again... also make a text file containing ALL of your serial numbers and copy that file as well