| Number | PWBRMAKE Warning |
| U4500 | UNKNOWN WARNING Contact Microsoft Product Support Services |
| An unknown error condition was detected by PWBRMAKE. | |
| Note the circumstances of the error and notify Microsoft Corporation by following the instructions on the Microsoft Product Assistance Request form at the back of one of your manuals. | |
| U4501 | ignoring unknown option option |
| PWBRMAKE did not recognize the given option and ignored it. | |
| U4502 | truncated .SBR file filename not in database |
| The given zero-length .SBR file, specified during a database update, was not originally part of the database. | |
| If a zero-length file not part of the original build of the database is specified during a rebuild of that database, PWBRMAKE issues this warning. One of the following may be a cause:
|