Versions: 5.5, 5.4, 5.3a, 5.3, 5.2a, 5.2

Problem Description

After a recent update of the McAfee antivirus software, it flags a COMSOL file as a dangerous file and removes it, leaving COMSOL in a broken state.

When trying to launch COMSOL, I get an error saying:

Could not find class 'com.comsol.bridge.Bridge' from bundle 'com.comsol.bridge'
For details, see the log file in COMSOL's preferences folder:


To get COMSOL Multiphysics back to a state where it can be run, you need to recover the files from the McAfee quarantine, and then whitelist them locally on your computer.

The files have now been whitelisted with McAfee.

if you have Engine Version 4087.0 (2020-05-28) or later the whitelist should be included. However, you will still need to restore them manually from the quarantine if they have already been quarantined. See instructions in item 1 below.

1. Restore the removed files from McAfee Quarantine.

  • See instructions in McAfee's Knowledge Base here.

  • If no files are in quarantine you have to use COMSOL Setup to repair the installation. Start COMSOL Setup and click Add/Remove Products and Reinstall and make sure to select the Reinstall selected and installed products check box. Use the Setup shortcut located in the COMSOL Multiphysics installation directory. The default path for the installation directory is C:\Program Files\COMSOL\COMSOL55\Multiphysics. If you are using the OnAccessScan functionality in McAfee, you will need to disable it during the COMSOL installation, as it otherwise will quarantine the files during the installation.

2. Add all the removed files to your local whitelist.

See instructions in McAfee's Knowledge Base here

The following files need to be whitelisted:


where <comsolinstalldir> should be replaced with your COMSOL Multiphysics installation directory.

Finally, make sure to not run a manual scan on the COMSOL directory as this will still remove the whitelisted files.