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hyphos
Participating Frequently
August 5, 2025
Answered

Lightroom Classic Unusably Slow and hanging while also slowing down whole pc

  • August 5, 2025
  • 5 replies
  • 948 views

Whenever Lightroom Classic is open, let alone editing, it slows my whole computer to a crawl. Delaying typing in web browser and super-jittery movement of windows.

Now, in Lightroom, everything is slow menu-wise when importing, changing preferences, whatever. But, as soon as I add more than one mask, the whole program stalls and barely functions. Now, from my understanding, this shouldn't be happening with the specs that I currently have.

 

LRC version 14.4

Windows 11 Pro

Intel(R) Core(TM) i7-10700KF CPU @ 3.80GHz 

32.0 GB RAM

Nvidia RTX 3060 12gb

1 TB SSD with over 100 GB free

 

None of these resources are going above 75%, with most settling around 50% in task manager. What could be causing this app to make my computer so slow?

Correct answer Mark Carline

I just switched to a new PC and found Lightroom Classic was running *VERY* slow.  Been trying to diagnose it for a while and then today just uninstalled Avast and, BOOM! Back to normal fast speed.  I don't know why I didn't just use the Windows 11 anti virus as I have heard it's pretty good.

5 replies

M
Mark CarlineCorrect answer
Participant
November 6, 2025

I just switched to a new PC and found Lightroom Classic was running *VERY* slow.  Been trying to diagnose it for a while and then today just uninstalled Avast and, BOOM! Back to normal fast speed.  I don't know why I didn't just use the Windows 11 anti virus as I have heard it's pretty good.

    Claire H.
    Community Manager
    Claire H.Community Manager
    Community Manager
    November 6, 2025

    Thanks for confirming @Mark Carline that the solution worked for you. Glad it's running smoothly now! ^CH

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      hyphosAuthor
      Participating Frequently
      August 5, 2025

      I just found the problem.

      TLDR uninstall avast

      The problem is, Avast would continuously scan and slow down the whole computer to a stall. This happened on another occasion where an unreasonable problem like this showed up, and all I had to do was disable Avast. So imo, uninstall Avast and just use the built-in Windows anti-virus, it's improved significantly and works fine now.

        dj_paige
        dj_paige
        Legend
        August 5, 2025

        Can't you instruct Avast not to scan LrC catalog files and photos?

        Ian Lyons
        Community Expert
        Ian LyonsCommunity Expert
        Community Expert
        August 5, 2025

        @hyphos 

         

        Check 'Catalog Settings' to see whether you have 'Automatically writes changes into XMP' enabled. If it's enabled, then disable (i.e. uncheck) to see whether the issue is resolved.

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          hyphosAuthor
          Participating Frequently
          August 5, 2025

          Yeah thats always been off

          dj_paige
          dj_paige
          Legend
          August 5, 2025

          While @DdeGannes may be on the right track, I would also recommend that you make sure your GPU driver is up to date, and make sure that it is a Studio driver and not a Game Ready driver.

            H
            hyphosAuthor
            Participating Frequently
            August 5, 2025

            Yeah that was my first thought, I just updated to studio driver with a clean install and it didn't change much

            DdeGannes
            Community Expert
            DdeGannesCommunity Expert
            Community Expert
            August 5, 2025

            @hyphos , You indicate in your post "1 TB SSD with over 100 GB free".

            This is what's responsible for the slow performance of your computer. It is recommended to maintain at least 20 to 25% of free disk space on your computer.

            You presently nearly 10% available, your Operating System requires that for file swapping and the like.

             

            Regards, Denis: iMac 27” mid-2015, macOS 11.7.10 Big Sur; 2TB SSD, 24 GB Ram, GPU 2 GB; LrC 12.5,; Lr 6.5, PS 24.7,; ACR 15.5,; (also Laptop Win 11, ver 24H2, LrC 15.0.1, PS 27.0; ) Camera Oly OM-D E-M1.
              H
              hyphosAuthor
              Participating Frequently
              August 5, 2025

              Would this change if I have all my raw files in a seperate ssd with ~50% free? Because right now my 1TB is system and I have a 500gb ssd with all the raw files on it which I reference and import into Lightroom from.

              DdeGannes
              Community Expert
              DdeGannesCommunity Expert
              Community Expert
              August 5, 2025

              Where is the Lightroom sub-folder which has the LrC catalog file with support data and preview files located?

               

              Regards, Denis: iMac 27” mid-2015, macOS 11.7.10 Big Sur; 2TB SSD, 24 GB Ram, GPU 2 GB; LrC 12.5,; Lr 6.5, PS 24.7,; ACR 15.5,; (also Laptop Win 11, ver 24H2, LrC 15.0.1, PS 27.0; ) Camera Oly OM-D E-M1.
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