This is a limitation of the Trend Micro Scan Engine where it cannot tell that two files are parts of a compressed file. It treats them as separate files, thus, the file is detected as a bad zip file. The files will result in the Scan Engine returning an error code in the log similar to the following:
2010/11/19 06:58:15 GMT-06:00 [10700:4128007872] An error occured while virus scan upon message 'A1D2E7F2-27F6-B0C0-4548-DC23C1FCAC9C'. Error: -82 '
BAD_ZIP_ERR'.
BAD_ZIP_ERR'.
To bypass the '-82 BAD_ZIP_ERR' error code, edit the imss.ini file:
- Go to the /config folder, and then open the imss.ini file.
- Locate the [virus] section.
- Change the value of the "VSBIgnBadZipErr" parameter from "0" to "1". VSBIgnBadZipErr=1
- Save and close the imss.ini file.
- Restart the Scan Service.