Recently a user reported that a workflow had failed to execute. Upon review there was a load of missing steps with the error icon next to them. The exact error was “Invalid condition expression” and appeared against all steps that referenced a Custom workflow activity step.
At first this was confusing because there had been no recent deployments to the test organisation. It is suspected that the root cause of this error was due to a failure several days ago to Import the “assembly” solution which hanged on the platform probably due to fact that the solution DLL’s are over 18MB in size. We did an IIS reset before trying to re-import the assembly solution and then the solution import worked fine through the application.
The current theory is that previous solution import caused the workflows to become out of sync with the referenced CWA DLL steps. Following another IIS reset days later the workflow designer window showed all custom steps and the workflows executed as expected.
I suspect information is missing here for what actually caused the issue but at least it was easily resolved in this scenario though accept a full IIS reset seems a little extreme here? Perhaps there was a better way of handling it.
If anyone has a more comprehensive explanation feel free to share and will update this post accordingly! Thanks.