You'll have no conflicting issues. Only thing is you won't be able to open Vegas Pro 21 project files with Vegas 11.

You might even be able to copy the timelines from one to the other. The only thing that won't make it going from VP21 to VP11 are effects specific in VP21.

I own Vegas Pro 11 and Vegas Pro 21, Can I run both versions on my computer at the same time?

Yes you can, but why....? Projects created in VP11 can be opened and further edited in VP21. Also there are no features, AFAIK in VP11, which are not also available in VP21.

For what reason should I copy a VP21 timeline into VP11 as suggested?

Projects created in VP11 can be opened and further edited in VP21 AFAIK in VP11, which are not also available in VP21.

Yes, projects created in legacy versions can be opened ... but in terms of audio, there are many great sounding (third-party) 32 bit plug-ins that cannot be opened in later versions of Vegas. VP21 also has the x86 VST-2 plug-in display issue which plagued Sound Forge16 &17, I have 32 bit VP9 installed when I need a specific sound of a 32 bit plug-in. Many of which, (there are no 64 bit alternatives (soundwise).

@t-keats If one of your computers goes back to vp11, it might not run vp21 so well. If you edit a project in vp21 and need to port it back to vp11, you could in theory run both Vegas versions simultaneously on the same machine to copy and paste events back to vp11. But if you try that on the older computer, the chances of success diminish.. try it instead on the on the computer with more memory. If it's not a complex project, starting over would probably be more simple. Suggest you save any old vp11 projects with in a new name if edited with vp21 to avoid the issue.

Another potential problem would arise if you previously upgraded to a newer computer in the interim and tossed it without deactivating the Vegas license first. You may need to log into your Magix account and deactivate the dead computer's license first.

@t-keats this laptop has 14, 15, 16, 17, 18, 19, 20, 21, and 22 on it. All run fine. My older laptop as 5, 7, 13, 14, 15, 16, 17, 18, and 19 on it and all run fine.

@t-keats If one of your computers goes back to vp11, it might not run vp21 so well. If you edit a project in vp21 and need to port it back to vp11, you could in theory run both Vegas versions simultaneously on the same machine to copy and paste events back to vp11. But if you try that on the older computer, the chances of success diminish.. try it instead on the on the computer with more memory. If it's not a complex project, starting over would probably be more simple. Suggest you save any old vp11 projects with in a new name if edited with vp21 to avoid the issue.

Another potential problem would arise if you previously upgraded to a newer computer in the interim and tossed it without deactivating the Vegas license first. You may need to log into your Magix account and deactivate the dead computer's license first.

Could you explain which benefit and sense it makes to copy/paste a VP21/22 timeline into a VP11 timeline on the same computer? What can VP11 that VP21/22 can't?

@3POINT I do that on occasions when a new version of Vegas has a new bug and I get too far down the editing road with the new version to want to give up and start over with the older version. But I only do things like that on a computer with lots of memory.

@Howard-Vigorita A new bug in VP is mostly solved in the next build or by reinstalling the previous build. I never had the need to go a previous Vegas version with a Vegasproject (especially not from Vegaspro22 to Sony Vegaspro11).

@t-keats this laptop has 14, 15, 16, 17, 18, 19, 20, 21, and 22 on it. All run fine. My older laptop as 5, 7, 13, 14, 15, 16, 17, 18, and 19 on it and all run fine.

And which version do you use to make your edits?

@3POINT typically the newest one only. The others are mainly there for testing - either testing scripts in older versions or if someone on the forum says "I have version 18 and it does this..." then I can test in 18 as well and/or compare to newer versions.

I had been doing all my edits on a 14 year old DELL desktop using VP11. No issues.

A few months ago, I bought a new DELL XPS 8960 desktop running Windows 11 Pro. Also bought the VP21 upgrade and thought I might tweak a couple of my old VP11 projects from original source files using VP21.

My son recently started working on a 2 year old laptop (bought as used) and he has been having some trouble with VP11 crashing which it never did on his 6 year old laptop. The newer machine was delivered with WIN 11 and he rolled it back to WIN 10. Don't know if he missed anything in doing the rollback.

Does anyone know what version of Vegas Pro 21 has no bugs?

@t-keats No version of anything has no bugs. What version are you using?

Does anyone know what version of Vegas Pro 21 has no bugs?

To get the best editing experience, best to use always the latest build of each Vegasversion. Most ideal is to use also latest version, at the moment that is VP22B194.

@3POINT typically the newest one only. The others are mainly there for testing - either testing scripts in older versions or if someone on the forum says "I have version 18 and it does this..." then I can test in 18 as well and/or compare to newer versions.

For testing, helping and comparing a good idea, but for normal editing not needed.