This is a heads up on what I just ran into after upgrading to IE 9 on Win 7. Of course this happened at worst possible time, with promise to client that the full beta with the reports will be up tomorrow, with about a dozen or more Crystal Reports developed in last month as final phase of project.
Dev machine is Win 7 Enterprise x64, reports developed with Crystal 2011, then added to Visual Studio 2010 project with Crystal for Visual Studio installed. All software with latest available service packs. The app is ASP.NET, .NET 4.0 for the framework.
All the Crystal reports had been running fine in previous testing. This past weekend, I installed all Win 7 updates, and decided, heck, what could go wrong, so I upgraded to IE 9. Yes. You laugh. I wish I felt like it.
I just spent a half hour or more starting final testing of the reports, and suddenly most of them would appear to run, a page count would show on the web page when the report area and Crystal toolbar displayed, but BLANK PAGES displayed. Just once a few lines of print appeared to tantalize me, but totally inconsistent, with 95% of the time nothing appearing. After fiddling around for a while, I just clicked the printer icon anyway, and the report printed, to the printer. Display on screen in web page: BLANK.
I found this KB entry at Microsoft: http://windows.microsoft.com/en-US/windows7/how-do-i-install-or-uninstall-internet-explorer-9
I uninstalled IE 9. After reboot, IE 8 was automatically restored.
I ran the app out of Visual Studio dev environment again, and (THANK $DEITY), the reports started displaying when executed in the web page.
FWIW, another data point, it occurs to me that the invisible reports all had lots of pages, e.g. 70 plus pages. Other reports that were only a couple of pages long displayed one the web page when CrystalViewer executed them just fine.