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Why does On1 have small sidecars?



  • Brian Lawson Community moderator

    ON1 is a company, not a program. Their programs (I'm assuming you are running Photo RAW but it doesn't really matter for this) are non-destructive. They do not touch your original image files whether they are RAW of some pixel format. Your edits and metadata changes (also edits) are stored in 2 places - an internal database and in the .on1 sidecars. The Keyword AI feature is finding new keywords to apply to your images and it is creating the .on1 files to store that information.

    You can remove them. You can also turn them off. I do not recommend this. If you should ever have to  Reset the program for some reason (and I have had to do it more than once) you will LOOSE EVERYTHING! Reset wipes out the internal databases so there go all your edits. If you have the .on1 sidecar files the program will be able to recover the edits and metadata changes you've made and it will rebuild those databases. If there are no sidecar files there isn't anything to use for rebuilding anything.

    If you really want to turn them off go to Preferences > Files and turn off the option for saving them. I DO NOT RECOMMEND THIS! You can also turn off the auto keywording feature so they are not being created for photos you have not edited and those that you export. It is in Preferences > Keyword AI.

    If you have some program which places limits on the number of files it can work with, you need a different program IMO. Do not let some arbitrary piece of software tell you that you cannot store as many files as you want on your system. That is their limitation and they should not be imposing it upon their users.

  • Rick Sammartino Community moderator

    You don't say which sidecars you're referring to. The .on1 sidecars can be turned off in preferences but then they won't be available if the database crashes or you move files.

    • on1 sidecars contain photo raw edits and metadata for portability
    • .xmp sidecars contain metadata for compatibility
    • if you delete your photos in Photo Raw, the sidecars will go too. If you delete outside, then you need to clean them up yourself
    • if you have Keyword AI enabled in Photo Raw, it will create a sidecar for every photo to contain that metadata. You can disable Keyword AI if you don't need it.
    • All of this is described in relevant locations in the user guide.


  • John McClelland

    Brian, thank you for the clarification of how sidecars are made and what creates them.  I will see if the other program allows exclusions and will check with a small sample. I learned Lightroom well, so have hung onto it.  

    Now that I am retired, and re-thinking, what is important to me, as far as photo usage, over the last 25 years.   I am finding the problems using a catalog, but learning a different way is challenging, for me. I used to read manuals cover to cover, but find it more difficult now. 

    Thank you for the suggestions and warnings.  I find I learn more from my mistakes, than successes.  If that was true, then I should be an expert by now!

    Rick thank you for screenshots. I give the warnings much thought. 


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