SSRS Error 'Report schema already contains a dataset with name"'

While working on the PSAProjInvoice report, I suddenly received this error.  Literally... I generated one report, then generated another 5 minutes later and the error showed up.

So far, all the suggestions here haven't worked.

Looks like the only way I could get out of this mess was to export out older versions of the Report and DP and import them into my dev.  Make sure you export our your DEV versions so you have all the code changes and report design changes.  Then import the old versions and it should be good to go!

Workflow email approvals error 'The requested workflow action failed.'

We have external users who approve time sheets.  One of these users was attempting to approve time sheets when they received the error.  In looking at the event viewer on the server that was running the 'Mobile connector app' service, I found a 'Failed to log on to Microsoft Dynamics AX.'  Further investigation revealed that after a reboot 4 days ago, the service never fully started.
Once we restarted the service, everything worked!