Sitefinity 3.7 newsletter module error

This morning one of our clients reported that clicking on the Newsletter module tab in the Sitefinity’s administration produces an error.

The reason is Sitefinity automatically generates service assembly in /Sitefinity/ServiceAssemblies/3889AC4AF542BAC3C62ABB154E78FEA8.dll

This dll depends on the host machine and Sitefinity’s version among other things.

So if you copy the site from other place then most likely you will get the error when trying to access the newsletter module.

If you search Sitefinity’s forum you will find that deleting the dll should force Sitefinity to regenerate the dll. However sometimes you still get the error even after deleting the dll.

One thing that I found useful is dropping the newly regenerated dll into the bin folder. It always fixes the problem for me.