Problem:
You need to move back to a previous service pack of the Crystal runtime engine or your Crystal runtime engine is corrupted. Maybe you even try to run a Crystal runtime installer, but it does not install properly.
Answer:
The only way to fix this issue is by manually uninstalling the current service pack, manually cleaning up any remaining files and/or DLLs, and (re)installing the Crystal runtime service pack of your choice.
Follow These Steps -- All Of Them -- Don't Skip A Step:
1) Uninstall the current SAP Crystal Reports runtime engine using your Control Panel.
DO NOT UNINSTALL REPORT RUNNER. Do NOTHING with Report Runner (except make sure it's not running during this process -- exit the app).
DO NOT UNINSTALL CRYSTAL REPORTS. It is not necessary, and it has nothing to do with any of this. It's a separate product installed to different directories.
2) Reboot your machine after uninstalling the runtime engine in step #1. The Crystal runtime is quite large and sometimes files are left over even after uninstalling, so we need to make sure the install is gone. Rebooting will finish uninstalling any DLLs that were still in use.
3) Sometimes the uninstall does not clean up the files/DLLs properly. Verify the Crystal runtime engine is gone by MANUALLY DELETING the Crystal Reports for .NET Framework 4.0 directory in Windows Explorer:
32-bit edition:
32-bit machine: C:\Program Files\SAP BusinessObjects\Crystal Reports for .NET Framework 4.0\
64-bit machine: C:\Program Files (x86)\SAP BusinessObjects\Crystal Reports for .NET Framework 4.0\
64-bit edition:
32-bit machine: N\A
64-bit machine: C:\Program Files (x86)\SAP BusinessObjects\Crystal Reports for .NET Framework 4.0\
4) After rebooting and manually deleting the Crystal directory referenced above, download and install whatever service pack you're moving back to or use a link provided by Support.
You can download all/any service packs here:
https://help.reportrunner.com/knowledgebase/article/installing-reinstalling-net-4-or-the-crystal-reports-runtime-engine-manually-and-service-packs
Note, the Crystal Reports for .NET Framework 4.0 will exist and have files in it again after this install/reinstall.
