TRI-V wrote...
I am trying to track MAC ID's in EXCEL. I can create a hex
address
such as A0FF156D421B but I need to display and print it as
A0:FF:15:6D:42:1B but I have failed to create a custom format
type

First, system administration using spreadsheets is a really bad idea.

Second, Excel provides NO SUPPORT WHATSOEVER for hexadecimal numbers.
Your hex ID, A0FF156D421B, is a text string, nothing more. That means
there's no possible way to create an Excel number format that would do
anything at all with it. However, as a text string, you could easily
separate bytes with colons.

=MID(MACID,1,2)&":"&MID(MACID,3,2)&":"&MID(MACID,5 ,2)&":"
&MID(MACID,7,2)&":"&MID(MACID,9,2)&":"&MID(MACID,1 1,2)
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