Opps... @j-v beat me too it. That is the solution.

Hey,
thank you for your suggestion! Unfortunately there's no .ofx.bundle folder to copy into my Vegas 20 path. I uninstalled Mercalli after my license had been expired for a few months and also Vegas 18 after I upgraded to 20.

The new installer seems to copy the four plugins individually as dll. I have attached a screenshot of how the installation works and what ends up on the hard disk. I really have no idea what else to do. I reinstalled Vegas 18 to check if it pops up in there but it doesn't. All other plugins work fine immediately.

Little update: I just installed my old Mercalli version as well as the trial for v6. I even installed my old Vegas 18 version (in which Mercalli used to work) and... doesn't work either. No of the three Mercalli versions works in any of my Vegas versions. Very weird. Well, at this point, I give up. If anyone has the same problem or knows a solution, I'd love to hear from you.

Write to Prodad - they are very helpful!

@neverusedamac 

you have a reduced Magix 5 plugin, which is not the same as the full version, which includes the one for Vegas. I used to get it for Video Studio, but it turned out that it was not for Vegas, it was not included. Of course, you had to pay to upgrade to the Vegas version...

Now that version 6 is out, it again doesn't have the Vegas plugin. I received an email from them informing me that it will be available later.

This is what the installer for the Vegas version looks like:

Write to Prodad - they are very helpful!

Agreed 100%! They were extremely helpful in my experience.

There is the Magix Mercalli for Video Pro X and Movie Studio (Movie Edit Pro), and a Vegas Mercalli. They are entirely different and looking at your installation, it plaining refers to MAGIX and not Vegas.

I just ran the Mercalli V5 Suite installer and this is what you should be seeing. Again, you are trying to install Magix (VPX and MEP/MS) and expecting it to work in Vegas. It won't.

Note that you do not see any .dll's but .ofx

There is the Magix Mercalli for Video Pro X and Movie Studio (Movie Edit Pro), and a Vegas Mercalli. They are entirely different and looking at your installation, it plaining refers to MAGIX and not Vegas.

I just ran the Mercalli V5 Suite installer and this is what you should be seeing. Again, you are trying to install Magix (VPX and MEP/MS) and expecting it to work in Vegas. It won't.

Note that you do not see any .dll's but .ofx

Thanks for pointing this out. Didn't even notice that! That makes sense. It's still weird that my old Mercalli version doesn't work either, even though it's definitely for Vegas as I used it back in VP18. But that's a different story I guess. Thanks for taking the time and all your answers! Appreciate it.

At this time, there is not a Mercalli 6 plugin for Vegas Pro as yet. Mercalli 5 SAL is excellent IMO and I've been using the 5 SAL for years rather than as a plugin in Vegas Pro. I've also got Mercalli V4 for Vegas Pro and, as per @j-v 's advice, copying the ofx.bundles - and there are in fact two bundles being the stabiliser and CMOS bundles - from the VP19 (or earlier) into the same folder in Vegas Pro 20 works - I just did it again.

Maybe resetting Vegas Pro 20 back to its default (factory) settings might clear out any blockages - https://www.vegascreativesoftware.info/us/forum/faq-how-can-i-reset-vegas-pro-to-default-settings--104646/ - and then try the copy/paste of the Mercalli bundles again.

But you do need to have installed your older version of Mercalli that previously worked in VP18 and copy the Mercalli bundles from VP18's OFX Video Plug-ins folder.

And even though I have VP20 installed, it doesn't show up in the list of Vegas installs, so I had to do as @Dexcon and @j-v mentioned. Copying the necessary files to the same location but for VP20.

For those Vegas 20 users who cannot successfully install Mercalli V5 Suite Vegas version:

Download Mercalli V5 for Vegas: https://www.prodad.de/support/mercalli/mercalli-50-vegas64bit.exe

Then double-click mercalli-50-vegas64bit.exe,

Then copy all folders of "C:\Users\YourName\AppData\Local\Temp\WZSE0.TMP\current\.ofx" to "C:\Program Files\Common Files\OFX\Plugins", ( "YourName" is your system account name. )

Then continue the Mercalli installation (regardless of whether it lists Vegas 20 or not) until the end, open Vegas 20, you can see Mercalli.

@lan-mLMC

Unfortunately your workaround doesn't work for me.

Vegas hangs at the creating video plugin stage. Factory reset doesn't solve the issue as well . If i delete the 4 prodad folders from C:\Program Files\Common Files\OFX\Plugins , Vegas starts normally.

Using VP20 latest built on Windows 11 22h2.

Vegas hangs at the creating video plugin stage.

@GJeffrey This means that Mercalli OFX was installed in the correct location and Vegas 20 detected it.

However, Vegas 20 on your system does not seem to cooperate well with Mercalli. On my system, they are correctly displayed in Vegas 20.

But you also have to have Mercalli 5 installed. Vegas just seeing the OFX in the folder will not get it to work.

Mercalli has to have a folder in C:\Program Files\proDAD\Mercalli-5.0

But you also have to have Mercalli 5 installed.

Of course, the last step above has already particularly mentioned "Continue the installation of mercalli-50-vegas64bit.exe".

Its function is exactly to install Mercalli common files in the directory "C:\Program Files\proDAD\Mercalli-5.0".

Maybe a rebuild the the plugin cache in the AppData\Local\Vegas Pro folder might work.

Deleting the cache manually (which is the same as a factory reset AFAIK) doesn't work either.

It looks like Vegas hangs when trying to build the plugin cache for 3 out of the 4 Prodad ofx plugin (only Cmos cache filed are created).

If i delete the 3 other plugin from the OFX/plugin folder, Vegas can starts normally and Prodad Cmos fx is available.

Might it be a problem with Windows?

I can't say if it's a Windows problem or not. Above my pay grade. I've ran out of ideas. Next would be to contact proDAD directly. Or try Revo Uninstaller Free to uninstall Mercalli 5 and let it hunt through the registry and folders to look for strays.

I have the Pro version. With another piece of software where I was having nightmares getting to work, I used Revo to remove every bit of it. Then ran Ccleaner to check the registry again. This was a last ditch effort and I had nothing to lose.

Thanks for your suggestion @Reyfox

I uninstalled Mercalli with Revo uninstaller, clean everything up, use Ccleaner then reinstall, still the same.

For the sake of trying, i installed VP18, uninstall Mercalli with Revo then install Mercalli again. This time I had the installer recognized Vegas 18 and it installed the plugin under program files/Vegas/ofx plugin.

I started Vegas 18, same behavior as VP20.

I reallystart to believe that there is an issue with Prodad installer.

I will contact Prodad and see whether they have a solution. But i doubt it further to my post experience with their customer support.

As I wrote, my one brain cell has ran out of ideas to try.

Out of curiosity, have you ever run sfc /scannow on your computer?

I reallystart to believe that there is an issue with Prodad installer.

I will contact Prodad and see whether they have a solution. But i doubt it further to my post experience with their customer support.

@GJeffrey
Do you have a bad experience with ProDad support?
I have only good ones.

@walter-i

Yep, again now

I contacted prodad support about my issue with their plugin few hours ago and explain them all i did.

Reply from them: no problem from their side with VP20, copy ofx plugin folders structure from v19 to v20.

1. I don't have vp19 but 18

2. VP 18 also hangs on startup.

That's a completely useless answer...

@Reyfox

Sfc /scannow throw me one error (bthmodem.sys) which has been fixed. I reinstall Mercalli, same issue.