System.InvalidOperationException: Unable to generate a temporary class (result=1)

Question

I have developed an application using .net 3.5 and have deployed it as an .exe on a number of machines with the same environment. However, on one particular machine I get th

Answer 1

XML Serialisation works by generating code to perform the serialisation. This is done in a temporary assembly created for that purpose the first time it is needed.

However this relies on being able to write the assembly to disk.¹

Your options are either to (1) given the user account which is running the process write permission (for an ASP.NET application this is likely to be a bad idea). (2) Use the SDK tool (sgen.exe) to pre-generate (at development/compile time) the serialisation assembly, and then use (and deplot) that assembly.

¹Open question: the APIs exist to create assemblies dynamically in memory: why not do that?