We have some Visual studio 2010 crystal reports accessed through our web application developed in VS 2010 c#. There have been 3 occasions in the past 2 months when they stopped working and presented the user with a blank page and internal error message of 'Unable to load the report'. In all 3 cases which were anywhere from 2 weeks to 1 month apart, the reports were working fine one day and the next day all users got the blank report. Since I found no system errors or changes and no code changes, I just copied the same compiled code without changes over to the production folder overwriting its content and the reports started working! The code I copied and the code that is there are identical including permission and modification dates . Just the act of copying corrected the issue. In fact once when the error happened I backed up the production folder to a temp folder and copied that same code from the backup back to production and that also fixed the problem! Not sure what is causing this but it is creating quite a problem. I searched quite a bit and others having a blank report problems have it from the get go. And that is when they move to a new server. Ours works in production and suddenly stops working. Our production machine is a windows 2003. Please let me know if you have any ideas why this happens.
Thanks,
Reza