I have a feature I'm adding to 4.5 (beta should be updated very soon) that has a step by step plugin replacer. This plugin replace experience is not good and it's a priority to get it fixed.
If you wish, you can send me your rack file and both plugins.xml and plugins64.xml (email to support with a good subject line to help me correlate that to this). I can take a look and do the edit for you.
I can't say where your rack file is but the plugins.xml and plugins64.xml are in C:\Users\<user>\AppData\Roaming\Brainspawn\forte 4.
Mike, I also get the forte has stopped working message when closing a rack sometimes. And it does seem like it's after I've had the rack open and have been playing for some time, maybe an hour to up to 4 hours. I mostly see it at the end of a gig, where the rack may be on for 3 to 4 hours without a restart of forte. I usually restart forte between each set, partly for this reason.
I know this seems complicated, but at the core its maybe too simple. Forte loads plugins based upon the CLSID string found in the rack file (XML text) and the plugin database (plugins.xml and plugins64.xml).
The Plugin Manager, which discovers plugins, scans folders and builds one of two files: plugins.xml = 32 bit, plugins64.xml = 64 bit. So if you just install Forte 32 bit and 64 bit and run both plugin managers you will have both files and could then compare them to see if different CLSIDs were being created for each. For VSTs the CLSID is generated by Forte based upon VST ID + VST DLL name. So having different DLL names would result in different CLSID strings between 32 and 64 bit databases.
The rack simply refers to a CLSID (doesn't care if 32 or 64 bit.) If you load 64 bit forte and load your rack that used to work on 32 bit, it might not find the 64 bit plugin if the CLSID is different.
To fix this, you could load the Rack file XML in a text editor, and do a search/replace on the old CLSID.
I really hope to add a new/better plugin replacer feature soon.
Ok great. There's a few things you do in/with Kontakt to make it run smoother (mind you this won't fix the opening/closing problems).
1. Exclude Kontakt from receiving blobs on scene change and use Kontakt's banks with bank change+program change messages on scene change to switch sounds.
2. Disable Kontakt's own Multiprocessor support as forte is already itself optimized for multicore processing.
3. Lower the Instrument preload buffer size in Kontakt. Depends on your cpu and if you use SSD's how low you can set this. You should be able to set it to at least 30kB from the default 60kB.
4. Run your Kontakt instruments fully purged. You can try this if you have a sufficiently fast CPU and run off SSD's. The idea is that all your Kontakt instruments don't have any samples loaded and load only te required samples as you play.
Another option is to purge the instruments, play through your piece(s) once to load only the required samples and then save again, so the instruments are ready to play with only the samples you actually use.
If you have JBridge, you can load 32 bit plugins into x64 Forte. However, although its a good product it complicates the setup and creates more uncertainty when something goes wrong. Typically if you go to 64-bit plugins, I'd recommend you should probably just go to 64-bit plugins too.
If the plugins are the same DLL name and plugin ID, the same plugin CLSID would be generated and it should just work. If the plugin DLL Name is different it may require a rack edit or adaptation to replace plugin identifiers in the rack file.