HELP I'm stuck - C:\HC BASE\COL

June, maybe you have read that post from yesterday:

https://forums.adobe.com/inbox

it gives you ideas about dealing with duplicates.

Mai_  wrote As an example I have 6 photos all the same - when I click on them and see their properties, one is in a folder I want it to be in, one is in another folder I want it to be in with a different but appropriate name but the others all say that they are in C:\HC BASE\COL00003 (or some other number).

I don't know what the C:\HC BASE\COL00003 is for, but I would not be surprised if it were the result of a backup system present in your computer.

Before I start deleting these I need to know what they are and can I delete them, or should I delete most of them and leave just one.

Yes, that is the problem with dealing with duplicates. Delete from catalog and/or disk, hide or stack in the catalog... No software can decide for you. As mentionned in the above post, there are external tools which can select duplicate and offer some kind of criteria like date or size to delete the files. They may be useful as such, but they also can help you in showing the reason of the duplications. Generally, you don't duplicate a single file, you duplicate a whole batch; and it's more effective to delete by batches.

A few more ideas if you really agree with the way you should work with catalogs, tags, stacks and albums. If your catalog keyword structure is ok, don't lose too much time in trying to clean up an horrible folder structure. It's not that important if you leave duplicates on your computer but your catalog is ok. That can mean the duplicates are not imported in the catalog, they are deleted from catalog, they are 'hidden' or in a stack for easier visual retrieval. If you have several copies of a file (same size in kilobytes, same date_taken and same embedded keywords or caption) it does not matter which is kept, except if you also want to clean up your folder structure.

Try to estimate if you have really to many duplicates so that becomes a problem for your available disk space. I don't mind keeping some duplicate files in my disks if they are not in the catalogs. For instance, use your explorer or finder to estimate the size on the disks, and compare to the size of your catalog; the best way is to initiate a full backup and stop the process when you are shown the size of the backkup.

Deleting a big number of files from the organizer can be a problem (see the other discussion).

Trusting the process in the organizer to filter duplicates will greatly help in most cases (repeated imports). For scans from different sources or dates, visual duplicates searches are useful; you can stack such duplicates instead of delete them.