Convert L01 to ZIP

As it stands right now, I have a logical collection (about 10 GB) of a PC in L01 format. I've tried to mount the image and zip the mounted drive however, 7zip throws an error of duplicate file names within the same folder.

To me, that's a situation that should not happen. That is, I would not worry about how deliver apparently incorrect image content as a zip archive. I'd worry about why you run into the situation at all. It suggests some kind of error in tools or handling.

What is that 'duplicated' file really about? Is it duplicated in the L01 image? Why? (An imaging tool or configuration that makes a second pass and adds updated files?) Or is it some unusual situation that makes your mounting software report two separate files – perhaps it's an ADS situation? Perhaps a filename containing special characters in the original file system, that are not preserved by the L01 image creator, by your mounting software or by 7zip, and so appears to be the same path but really isn't? Or perhaps even a bug in your mounting software? Or some other anomalous situation? You have to research that on your own.

If you have all those angles covered, you will simply have to deliver two archives 7zip clearly cannot cope with the situation. (Or use a ZIP tool that can – but expect your client to run into the same problem on his end …) Be prepared to field any questions as to why you're doing that – as well as answering all questions about having what appears to be a duplicate file. And if it is a question about file path content being lost (the 'special characters in file name' case) you may need to be prepared for some pointed questions on forensic soundness on your end.

There are IMHO two different aspects to deal with
1) the duplicates error message
2) the issue with long path names

I believe that #2 is not connected with 7-zip (that AFAIK has not the 256 character limit in paths) but rather to the "source" (the mounted L01).

Usually these problems can be (sort of) solved by shortening the paths either using SUBST
https://support.code42.com/CrashPlan/4/Troubleshooting/Windows_file_paths_longer_than_255_characters
or, if you use Windows 10, by Group Policy/Registry Edit
https://www.howtogeek.com/266621/how-to-make-windows-10-accept-file-paths-over-260-characters/

but the first way may (further) compromise the information, and the second might only move the issue to the customer's machine(unable to access/read the data).

The third possible solution is to use the Win32 File Namespace, i.e., example, \\?\C which works just fine in 7-zip and - provided the mounted L01 provides it - bypass entirely the limitation
https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file#maximum-path-length-limitation

still, it has to be seen if the customer will be able to access the resulting .zip

Maybe you can try libewf ewfmount to mount the L01 (cannot say if the Windows version does support L01).

For the #1 I as well suspect that the issue is in the "source file" or in the way it is mounted/made accessible.

jaclaz