Although I don't have Twixtor, if it worked in previous versions of Vegas Pro that you may have, presumably the same install process would exist with Vegas Pro 19 based on Twixtor's compatibility information.

@Dexcon and @Dmitriy-Makutenus - Yup, integrated fine:

PluralEyes
After installing copy the file "PE4VegasLoader14.dll" located in C:\ProgramData\VEGAS Pro\14.0\Application Extensions and paste in C:\ProgramData\VEGAS Pro\Application Extensions

Twixtor
All versions of Twixtor OFX are compatible with Vegas Pro 19

PluralEyes works fine with VP 18 and 19 as well once you copy these files over. If you have problems with that feel free to ask for help.

AudioSyncR works better than Pluraleyes, and is a whole lot less expensive. Links to demos are here:

https://www.vegascreativesoftware.info/us/forum/happyotter-audiosyncr-a-new-tool-for-syncing-audio--130392/

PluralEyes works fine with VP 18 and 19 as well once you copy these files over. If you have problems with that feel free to ask for help.

Would one of you be so kind as to send me the .dll? Or upload it to a link? I managed to delete all of mine on the old computer. 😭

Would one of you be so kind as to send me the .dll? Or upload it to a link? I managed to delete all of mine on the old computer. 😭

@Ahimoteb99 - Really? How would a .dll help you? I’m willing to learn.

Would one of you be so kind as to send me the .dll? Or upload it to a link? I managed to delete all of mine on the old computer. 😭

@Ahimoteb99 - Really? How would a .dll help you? I’m willing to learn.

I'm guessing that PE4VegasLoader14.dll is the script that loads plural eyes into Vegas 17. I've not been able to find it online and don't have the old files.

If it doesn't get added to the folder upon installation, Maxon support can likely provide it.

I am using Pluraleyes 4.1.11 in Vegas Pro 18 and also latterly in Davinci Resolve Studio17 (which works in a different way to Vegas).
When I'd had problems getting Pluraleyes to work in Vegas on a new laptop a few weeks ago I found - as others have described in other posts on the forum - that I needed to copy 
PE4Vegas14.dll and PE4VegasLoader14.dll
from 
C:\Program files\Red Giant\Pluraleyes 4\
to
C:\ProgramData\Vegas Pro\Application Extensions\
(Pluraleyes 4.1.11 rather than an earlier version was required to work DRS17)

I found that working with Maxon was a real PITA. I found that I needed to download the entire Maxon Shooter Suite 13.1.14 to access and install the Pluraleyes app. Then some jiggery pokery to get Maxon to recognise my existing license. Maxon had reckoned to offer a support facility but it took more than a week to even respond! Meanwhile I'd clicked anything and everything and somehow got sorted.

I did try the newish inbuilt Vegas sync facility. It was very slow but it was a big bunch of files. Tried the inbuilt DRS17 sync facility as well and that was very fast. I'm still preferring PE though just in case of problems with very long audio file syncing. Expensive product now so if I were new to Vegas I'd probably go from the Happy Otter scripts.

Anyway I've uploaded these dll's to Google Drive. I've no idea if you can simply download and install them but give it a try at your own risk if you wish. I'll leave them up for a few days:
https://drive.google.com/drive/folders/1vAUJevYEAoW82_Uj0UcYRuJL8bHRe-Oi?usp=sharing

I copied those two dll files over and Pluraleyes over but the program still doesn't show up in V19. I still have in in V17. Any other ideas as to how to get it working again in V19. Thanks

Vegas 19 did involve some users in having to re-do some preferences etc - its discussed in the monster thread in Important Posts Vegas Pro 19 Updates 5 (Build 643) at the top of the forum page.

Have you got Pluraleyes 4.1.11 (5414) If not maybe you need that. You can download it from Maxon but since it is part of the whole Shooter Suite you have to run the suite - but just apply Pluraleyes.

If Pluraleyes is not showing in the Toolbar at the top of the screen try going to:
Options > Customize Toolbar
then in the Available toolbar buttons box  click Add to move the Pluraleyes icon (hopefully it is available there) to the Current toolbar buttons box, then click Close (or move it within that box to a more suitable position on the list for you, then click Close).

You may also find Pluraleyes within Tools > Extensions

You can see where the relevant dll's are to be found in this screenshot. You may have these already in which case I cannot suggest more: