can I view a file on my reef master program that someone else created on their reef master program?

What sort of file is it? Map exports in the AT5 format can't be reimported into ReefMaster, but pretty much any other sort of file can be. One thing to be aware of is when moving workspace (.rmdb) files, RM needs the original sonar files to be available for sidescan and sonar viewer functions (but not mapping).

a friend of mine has reef master and he started logging data and creating contour maps. he gave me the file from his trips that he created on reef master so I can have them on my Lowrance. my question is, now that I have the reef master program on my computer, can I view the info that he gave me on my computer in reef master?

It depends what sort of file he gave you. If he gave you a finished Lowrance map (in the AT5 format) then you can't view that in ReefMaster - you can only view it on a Lowrance unit. If you want to see his data on your ReefMaster, then the best thing to do is either get a copy of your friend's original sonar logs (the sl2 or slg files) and import them into ReefMaster - this would give you full access to all of the sonar data, so you could use the sonar viewer and sidescan mosaic features.
If you just want the maps then you can get a hold of your friends workspace file - this is the file that holds all of the workspace details, including tracks and map projects, and has the extension .rmdb. The only issue with sharing .rmdb files is the one I mentioned in my first reply - you won't have access to the original sonar data, so you won't be able to view sonar in the sonar viewer or sidescan mosaic functions.

Matt