Hello! I've stumbled on a bit of a mindboggler (perhaps). The situation is as follows, we have a customer with an SBS, with Exchange 2010 on it. As far as I've discerned, Exchange does not use anything but .net 2.0 in the applicationpools of the IIS. But, a third party company was installing a CRM system on the server, and this installed asp.net framework 4.0 on it. This CRM system is not supposed do anything to bindings and application pools, however, there are now entires in the application pools for the MSExchange-pools but with "Asp.net v4.0" added to it. And the Exchange-pools are now running on them, instead of the old regular .net 2.0 pools. Even though I wouldn't think so, is this expected behaviour? If not, is there a way to "properly" roll back the Exchange-pools to use the 2.0 ones? Setting the asp.net v4.0 entries to use 2.0 did not quite seem to do the trick. Also, I should mention that the mailserver is running, but it's not accessible through EMC, and when trying to do this you receive the error: "The following error occured while configuring help links: Could not load file or assembly 'system,version=4.0.0.0, culture=neutral, publickeytoken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified." Which points to the asp.net 4.0, though from what a quick look-up sounds like a permission issue. Any ideas?

Hi, I can't answer if this is normal behavior when installing a different software using IIS (I would never install a third-party application like this on an Exchange Server), but you should definetly change the .Net Framwork used for the Exchange Application Pools. It can be done by right clicking the pools, choose Advanced Settings and then just change the .Net Framework version in the drop-down list. When done, recycle the Application Pools. EDIT: Also, make sure the CRM Installation didn't mess with the IIS Bindings. Martina Miskovic

What does the recycling actually do? Mostly thinking recycling versus changing version and stopping/starting the pools? And the CRM system did not do anything with the bindings, that has been doublechecked a few times. And would this be on the new entries (asp.net ones) where the applications currently reside? Does Exchange have a namedependancy on the application pools or are they just administrative?

Hi, Ok, good that the CRM System didn't mess up the bindings. Recycling is kind of the same as restarting. Just change the Application Pools used by Exchange and that includes the one called DefaultAppPool. The names are hardcoded so don't change them. Martina Miskovic

This solved the problem. The only question that remains is the exact difference between stop/starting services and recycling, but the Exchange is now running as it should again.