We have a program that uses the function module PRELIMINARY_POSTING_FB01 to park journal entry documents. We recently encountered the error “Enter rate GBP / USD rate type M for 00/00/0000 in the system settings” (SG105) coming back from this function module.
Of course the first thing we checked is that we had the M conversion rate set up correctly in transaction OB08, which we did. The interesting thing about the error is the date with all zeros. Even though the conversion rate was defined the program couldn’t find it because nothing is in effect on 00/00/0000.
Eventually we figured out that the function module uses the Translation Date (t_bkpf-wwert) to find the conversion rate. We were leaving this blank date which resulted in the above error. Populating this field with the correct value resolved the issue.