I have a similar situation to this question.
I have a custom sequential SharePoint workflow, deleoped in Visual Studio 2008. It is associated with an InfoPath form submitted to a form library. It is configured to automatically start when an item is created.
It works sometimes. Sometimes it just fails to start.
Just like the question linked above, I checked in the debugger, and the issue is that the InfoPath fields published as columns in the library are empty when the workflow fires. (I access the fields with workflowProperties.Item["fieldName"].) But there appears to be a race condition, as those fields actually show up in the library view, and if I terminate the failed workflow and restart it manually, it works fine!
After a lot of head-scratching and testing, I’ve determined that the workflow will start successfully if the user is running any version of IE on Windows XP, but it fails if the same user submits the same form data from a Vista or Windows 7 client machine.
Does anyone have any idea why this is happening?
This occurs due to the fact that Vista/7 saves InfoPath forms through WebDAV, however XP uses another protocol (sorry, can’t remember at the time). SharePoint catches the “ItemAdded” event before the file is actually uploaded (that is, the item is already created, but file upload is currently in progress).
What you can do for a workaround is to add a dealay activity and wait for 10 seconds as the first thing in your workflow (will actually be longer than ten seconds due to the way workflows are built in SPPS). This way the upload will already have ended when you perform to read the item. To inform the users about what’s happening, you can add a “logToHistoryList” activity before the delay.