Exchange Server Transport Agent Won't Load, "Built By a Newer Runtime"

Question

I have built a simple transport agent (using .NET 4.0) for exchange 2010 and I'm trying to install it using the exchange management shell, but I run across this error:

Could not load file or assembly 'file:///C:\Program Files\Microsoft\Exchange Server\V14\Public\MySimpleAgent.
dll' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot
 be loaded.
    + CategoryInfo          : InvalidArgument: (:) [Install-TransportAgent], BadImageFormatException
    + FullyQualifiedErrorId : 3A033BB9,Microsoft.Exchange.Management.AgentTasks.InstallTransportAgent

I really only found one good public discussion of this issue, but the solutions suggested by some have not helped my situation.

I have:

Made sure that my project references both Microsoft.Exchange.Data.Transport and Microsoft.Exchange.Data.Common
Deployed my assembly(ies) to \Program Files\Microsoft\Exchange Server\V14\Public

Any other suggestions?

I haven't tried lower than 3.5, but I strongly suspect it won't matter because the technet discussion indicated that others had tried it to no avail. — Ben Collins, Jun 03 '11 at 22:32
I had the same error message. When i tried to compile with the framework 2.0 compiler gives me warning and tells me the Microsoft.exchange...dlls have dependencies over System.Core v3.5!!! and does not compile. — Mert Gülsoy, Mar 23 '16 at 17:20

score 3 · Accepted Answer · edited Dec 29 '11 at 22:22

3

I chased my tail for two days trying to figure this one out. The problem ended up being that the version of the Microsoft.Exchange.Data.Common and Microsoft.Exchange.Data.Transport dlls referenced in my project did not match the version of the dll's in the "public" folder on the hub transport servers. After updating my referenced dll's to the correct version the problem went away.

edited Dec 29 '11 at 22:22

animuson

53,861
28
137
147

answered Dec 29 '11 at 22:22

Nicholas J. Markkula

1,542
4
18
30

score 2 · Answer 2 · answered Jan 17 '12 at 13:00

I had the same problem a few days. My colleague installed the .NEt Framework 4.0 (without rebooting the server) and the problem was still there. After I read a lot of forum entries and tips and tricks I found the problem on my Exchange Server 2010. I only had to restart the IIS. After the restart I could install my transport agent without problems.

score 1 · Answer 3 · answered Sep 13 '11 at 15:12

1

Try to compile in 64 bit, it did the job for me!

answered Sep 13 '11 at 15:12

Batiste Frelet

31
5

score 0 · Answer 4 · edited Jun 20 '20 at 09:12

I had to compile as x64 and .NET 3.5 for the install to work (used VS2013)

Also doing iisreset helped because I did initially get the error even with .NET 3.5. Because w3wp had a hold on the file from me trying to repeatedly install it.

.NET 3.5 was required by the two references

Microsoft.Exchange.Data.Common

Microsoft.Exchange.Data.Transport

.NET 4.0 didn't work for me and I initially tried using .NET 2.0 following MS documentaion

Exchange Server Transport Agent Won't Load, "Built By a Newer Runtime"

4 Answers4

Linked