I have found some women's CC package files that other content creators have made and I would like to mark them as usable by men. I would upload them here, but the creators both have stated not to reupload and I want to respect their wishes. One is a hat, and another is a backpack. I would ask the creators if they would do it for me, but but one states that they are too busy, and the other hasn't updated in awhile (2014 seems to be the latest post). I have downloaded both pieces and they work with cis-gendered females just fine, but I would like to make the items (hat & backpack) unisex. Is there something that I can download to allow for this, or does the coding go much deeper than just a toggle switch? (In my mind I just think that downloading a program from here, load the package, hit a toggle, and rename so to make it different from the originals).

You can use CAS Tools: http://modthesims.info/download.php?t=582348
Open the package in the Clone Package Editor tab, in the General CAS Part Properties sub-tab you'll see checkboxes for age and gender. Just check both male and female, commit changes, and save as a new package.

If you have Sims 4 Studio, it has the same options in the Studio tab, Categories sub-tab.

I got an error message when trying to do the backpack. Should I post it here, or provide a link to the image?

Either one. You could also post a link to where I can download the backpack.

Here is the link to the backpack: https://sims4marigold.blogspot.com/...y-backpack.html

The 'Sub Type' field in the package is set to an invalid value. Set it to None before you commit and save and it should work.

Thank you - they both work now.