I recently received a file which contained unistrut framing
in its design .When I opened the file all parts were present except
for the unistrut .All unistrut parts are suppressed and cannot be
resolved .When I try to use the file replace option .It says I
cannot replace it with a file of the same name .Changing the file
path to the location of the uistrut does not help .
The file replace command is for replacing a part with a completely different file, so that command is not the appropriate one for resolving missing files. If you have the part files that the assembly needs, then resolve or unsuppress them in the assembly. If the assembly is looking in the wrong place, it will prompt you to browse to a new location for the file.
If you don't have all the parts needed, then contact the person who sent you the assembly. It's possible they modeled the Unistrut manually and just didn't include the files, but it could also be that they used the Unistrut members from the SolidWorks Toolbox. If you don't have Toolbox enabled and/or you are not sharing a toolbox library with this other person, then you will need to resolve your file sharing procedures to account for Toolbox usage.