If ever you require to create a GUID in excel here is a formula to get a GUID.
Please note that depending on your language and region settings the ";" might have to be replaced with a ",".
=LOWER(CONCATENATE(DEC2HEX(RANDBETWEEN(0;4294967295);8);"-";DEC2HEX(RANDBETWEEN(0;42949);4);"-";DEC2HEX(RANDBETWEEN(0;42949);4);"-";DEC2HEX(RANDBETWEEN(0;42949);4);"-";DEC2HEX(RANDBETWEEN(0;4294967295);8);DEC2HEX(RANDBETWEEN(0;42949);4)))