Color Index VBA stops working after save and closure

Hello -

I usually don't do forums, but at this point I'm desperate. I'm working on a project at work. The WorkBook has several tabs. The only VBA functions/sub functions I'm using are the

Function Color (CellColor As Range)
ColorIndex = CellColor.Interior.ColorIndex
End Function

Then also the Private Sub Function of Worksheet_SelectionChange.

The issue:

Yesterday after spending hours I figured out how to use a combination of the ColorIndex VBA and a ghost sheet to identify the colors of specific cells using an Index Match formula. Then I was on my way to throwing on the conditional formatting so that when a cell is highlighted on any other sheet (in work's case yellow) it will also transfer to the "Master sheet" where we can pull the information of 1 individual across all the sheets into 1 view. (Hence the Index Match)

It worked beautifully yesterday. I saved and closed with the intent of finishing the conditional formatting (Using the ColorIndex(range)=6 type formula.. that's not the whole thing but basically) that worked yesterday. Now the ColorIndex VBA won't work and returns a #Name? error. I have not touched anything on the VBA or the ColorIndex formula on the dummy sheet. I solely was applying the Conditional Formatting to the master sheet.

So I started over, only to find that this ColorIndex VBA at its basic application will again, stop working once the sheet is saved and closed and reopened.

Can ANYONE point me in the direction of why this is happening and how to get it to stop?

*Please note: all this VBA stuff I spewed above I learned in about a week, so my understanding is fairly limited... Explain it like a toddler to me lol*

Yes, so I did just close out all other books and start ALL OVER with a raw ColorIndex function and random information to get it to work.

Here's the thing. I followed instructions for the "enable macro" thing, and it's grayed out on my Excel. Now a co-worker did a function very similar to this (this has been a year long project that is basically recycled every quarter, and now I own it) and it has worked every time. We work at the same place so I'd assume the macro settings are the same for both of us. When I got the options, the only macro function I can change is "Trust VBA project object model"

Will that not be enough? Is this more of a "Hey tech, let me enable my macros" type situation?

Thank you in advance.

Got a fix... Turns out my job automatically disables macros unless the file is saved on a secure drive and I didn't know that. Thank you for your help!