Depending on the error message, do any of the following:
Case A
"An error occurred while trying to remove Trend Micro OfficeScan Client. It may have already been uninstalled. Would you like to remove Trend Micro OfficeScan Client from the Add or Remove programs list?"
If you encounter this error message, it means that Windows failed to find the OfficeScan client/agent uninstallation program (ntrmv.exe).
Please check if the following registry value is configured correctly. "UninstallString" refers to the full file path for ntrmv.exe.
Key : HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\OfficeScanNT
Name : UninstallString
Type : REG_SZ
Data : "C:\Program Files\Trend Micro\OfficeScan Client\ntrmv.exe"
For a 64-bit computer:
Key : HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\OfficeScanNT
Name : UninstallString
Type : REG_SZ
Data : "C:\Program Files (x86)\Trend Micro\OfficeScan Client\ntrmv.exe"
If you still encounter this issue, please check if ntrmv.exe exists in your OfficeScan client/agent installation folder.
Case B
"Unable to launch uninstallation program. Uninstallation aborted"
If you encounter this error message, it means that the uninstallation program, ntrmv.exe, was copied to the following folder and then executed.
%userprofile%\Local Settings\Temp\
You will receive the error message when the file copy action fails.
Make sure that your log on user has WRITE privilege to the %userprofile%\Local Settings\Temp\ folder.
If you still encounter this issue, try to delete all the files in the \Temp\ folder and try to uninstall the client/agent again.
Case C
"Unable to get uninstallation information (GUID). Uninstallation aborted"
Receiving this error message means that the OfficeScan client/agent uninstallation program, ntrmv.exe, failed to check the uninstallation information.
You will encounter this message when the following registry does not exist:
Key : HKLM\SOFTWARE\TrendMicro\PC-cillinNTCorp\CurrentVersion
Name : Database Path (REG_SZ) or GUID (REG_SZ), Server (REG_SZ), ServerPort (REG_DWORD)
For a 64-bit computer:
Key : HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\TrendMicro\PC-cillinNTCorp\CurrentVersion
Name : Database Path (REG_SZ) or GUID (REG_SZ), Server (REG_SZ), ServerPort (REG_DWORD)