Lightroom suddenly is slow in response, when I select next photo it takes 20 seconds to appear.

Hi Jasmine,

Thanks for reaching out. We are sorry for the trouble with Lightroom. We are here to help.

Could you please confirm the version of Lightroom you are working on? Go to Help > About Lightroom or Lightroom Classic to find the exact version number for the application. Does it slow down when working with any specific tool or operation?

Please go to Lightroom Classic or Adobe Lightroom  > Preferences > Performance > Use Graphics Processor > Set it to Off if it is on Custom or Auto. If this shows you any differences in performance, please check this article to troubleshoot further: https://helpx.adobe.com/lightroom-classic/kb/troubleshoot-gpu.html

If you are using Adobe Lightroom, you can pause the sync while working or during editing sessions, and then at the end of the session, resume the sync and let it finish before you exit the Lightroom App.

If you are using Lightroom Classic, here are a series of suggestions related to hardware & software optimization and other in-app operations you can do to optimize Lightroom Classic's performance in this article; and please give this a detailed read through: https://helpx.adobe.com/lightroom-classic/kb/optimize-performance-lightroom.html

We hope this helps,

Thanks!

Sameer K