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Rob_Cullen
Community Expert
Rob_CullenCommunity Expert
Community Expert
November 9, 2017
Answered

LRCAT-SHM and LRCAT-WAL are for ?

  • November 9, 2017
  • 3 replies
  • 16007 views

(Lightroom Classic 7.0.1, WIndows-10)

Why do these files exist in the catalog location?

What is their technical purpose?

I note they are temporary, like the '.LOCK' file, and disappear when Lightroom Classic closes.

      This topic has been closed for replies.
      Correct answer johnrellis

      These are temporary files created when LR has the catalog database open.  (The database is implemented using SQLite.)  See here for their technical purposes: https://sqlite.org/tempfiles.html

      3 replies

      J
      johnstonanthony
      Participant
      May 2, 2020

      From what i understand these LRCAT-WAL files are only temporary and present while LR is open. However, even when LR is closed I have multiple LRCAT-WAL files. Is it safe to delete them? They add up to about 8GB of my harddrives space

        bc73436340
        bc73436340
        Participating Frequently
        April 7, 2023

        Hello,

        I have exactly the same problem with multiple -lock, -shm and -wal files that do not disappear when I close Lightroom.

        Did you get a solution about this ? Have you deleted those files ?

        Thanks

        Bernard

        Maoc OS 12.6.3, Lightroom 12.2.1

          Rikk Flohr_Photography
          Community Manager
          Rikk Flohr_PhotographyCommunity Manager
          Community Manager
          April 7, 2023

          You’ve posted to a very old thread. It is highly unlikely that the issue described in this thread, though not impossible, is the same issue which you are currently experiencing. Rather than resurrect an old thread that is seemingly similar, you are better posting to a new thread with fresh, complete information including system information, a complete description of the problem and step-by-step instructions for reproduction. 

           

          In the unlikely event the issue is the same, we will merge you back into the appropriate location. 

           

          Thank you!

           

          Rikk Flohr: Adobe Photography Org
          V
          Vic-86
          Known Participant
          May 17, 2018

          OK, this makes perfect sense.

          Windows just did an update, and now Lr Classic won't start. I can use file manager and watch as the .lrcat-shm file is created and deleted, created and deleted, over and over. And nothing happens. The computer has been restarted several times, and I have deleted the lock .lrcart-shm and .wal files. Try to start Lr and the pattern repeats, endlessly.

          Help

          Win 10 on NUC w/Intel I-7, 32G RAM, M2 SSD, Current Lr & Ps
            johnrellis
            johnrellis
            Legend
            May 17, 2018

            I recommend reposting this in a new thread where more people are likely to see it and respond.

            johnrellis
            johnrellisCorrect answer
            Legend
            November 9, 2017

            These are temporary files created when LR has the catalog database open.  (The database is implemented using SQLite.)  See here for their technical purposes: https://sqlite.org/tempfiles.html

            Rob_Cullen
            Community Expert
            Rob_CullenCommunity ExpertAuthor
            Community Expert
            November 9, 2017

            Thanks.

            Unfamiliar with SQLite and had not seen these files before the recent versions of Lightroom.

            Regards. My System: Windows-11, Lightroom-Classic 15.0, Photoshop 27.0, ACR 18.0, Lightroom 9.0, Lr-iOS 10.4.0, Bridge 16.0 .
            johnrellis
            johnrellis
            Legend
            November 9, 2017

            Reading the SQLite documentation, it may be that LR 7 has moved to the "write-ahead logging" (WAL) provided by newer versions of SQLite, which is supposed to make updates to the database faster.  This would account for why you didn't see these files in older versions of LR.

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