When you import exchange rates, follow these rules:
Years in source but not in destination files are not imported.
Exchange rates for time periods in destination but not source files, are not imported. This also applies to subperiods.
The source file can have more detail than the destination file. For example, the source file can be in months and the destination file in quarters. However, the source file cannot have less detail than the destination file.
The source and destination files must have matching fiscal year ends.
If the source and destination files are password-protected, the passwords must match.