When Forte starts it updates a file called "plugins.xml" in the application data directory. This file is available using the Tools | View INI Files menu option. Plugins.xml contains information about each plugin found on startup and is called the plugin "cache".  As Forte starts, it scans through every DLL file in the VST search paths.  If the file is already in the plugins.xml cache, no additional action is taken.  If a new DLL is found that is not in the plugins.xml cache, it is probed to see if it is a VST plugin.  The DLL is loaded and certain signatures are examined.  If the plugin is not found to be a VST, it is put in the ignore list in the cache.  If it is a VST plugin, it is further probed for information like company name, etc. and placed in the cache.  

Missing Due to Incompatibility

Sometimes Forte will find a new VST DLL but fail to add it to the cache. Many times this is because the plugin has something about it that Forte doesn't support. Here are the boundaries:

  • The plugin must have its own UI. Older VST plugins that do not have UI's are not supported.
  • The plugin must have 0, 1, or 2 inputs. More inputs are not supported
  • The plugin must have between 1 and 64 outputs
  • The plugin must return a good pointer to its effect interface when asked.  This will often fail if a plugin is not correctly registered. One of a plugin vendor's favorite disabling tricks is to return a NULL value when asked for the AEffect pointer from main. 

Plugin Crash During Discovery

Another thing that can sometimes happen is that the plugin will do something illegal while Forte is examining it. This is called an exception and can cause Forte to crash during VST enumeration. When you restart Forte, you will be asked if you want to bypass that VST in the future and add it to the "ignore" list. If you wish to know why a plugin was not accepted into the cache, you can do the following:

  • Open Forte Preferences, General Tab, and select a log level of "Information"
  • Navigate to the Plugin preferences tab and select the option to rediscover plugins (or you can just delete plugins.xml, or if you are xml-savvy, you can actually just delete the XML element that represents the plugin in the bad list)
  • Restart Forte. When Forte excludes a plugin, it will now log the reason why.
  • Reexamine your log file.