Unable to find a version of the runtime to run this application

Question

Hello, this is confusing. My app is targeted to .Net2 version. When someone wants to run it at .Net4 version he gets this message and cannot run it. I have searched this forum and noone has the right answer.

There were some tips as this one:

Add to application configuration file theese elements:

<startup useLegacyV2RuntimeActivationPolicy="true">
<supportedruntime version="v2.0.50727" sku=".NETFramework,Version=v2.0.50727"/>
<supportedruntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup>

But this is not working. I have this config as embeded resource so I hope it is not caused by that.

 

Answer 1

Hi Muffon,

If your Application is using 4.0 Framework and you want to add framework 2 dll then above code is work.

if your application is in 2.0 framework and you want to add framework 4 dll then it's not possible.

if your Applications is built in 2.0 framework then you have to install Framework 2.0

 

Regards

Ishan

 

Answer 2

So I am not able to run app targeted to 2.0 on framework v4.0 ? Oh my god.

Answer 3

Hi Fishtraveler,

Since .NET Framework 4.0 is different from .NET Framework 2.0, you have to debug your application after you change the targeting
framework.

I hope this helps.

Best Regards,

---

Alexander Sun [MSFT]
MSDN Community Support | Feedback to us

Answer 4

Oh! is diferent, 4.0 from 2.0 but why i can't? is stupid

I need the 2.0 3.5 and 4.0 versions of .net because anything work well, but with the 4.0 i can't reinstall 2.0 or 3.5, "Setup cannot continue because this version of the .NET Framework is incompatible with a previusly installed one. For more information, see http://support.microsoft.com/support...........

will microsoft to make possible in FRAMEWORK 5.0 or next 5.01

Answer 5

We have a dotnet 2.0 app that - on the 64-bit machines, it won't let us install the 32-bit dotnetfx.exe, and when we install the 64-bit dotnet 2.0, it says it's already installed, but the app will not run, and it says: Unable to find a version of the runtime to run this application. One would think there would be an easy fix for this - a patch I could download and run. I do not have the time to debug this. The app is not tat important and I will just quit using it if there isn' an easy fix.  I hope everyone has a wonderful new year and merry christmas!

P.S. If you know a quick, easy fix, please post it and I, and many others, will love and appreciate you.

T I A

: )

Answer 6

"Add to application configuration file theese elements:

<startup useLegacyV2RuntimeActivationPolicy="true">
< supportedruntime version="v2.0.50727" sku=".NETFramework,Version=v2.0.50727"/>
< supportedruntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup>"

What file - where is this application confiuration file?

Thanks and warmest regads,

Flux B. Locker