I'm having the exact issue now!  Preparing a client to upgrade Sage from 2014 to 2020, but wanted them to get onto Win 10 first.  Did you ever find a solution?

Did you install all of the product updates?  I recall when I installed Product Update 3 there was an error relating to Crystal Reports that prevented previewing Crystal Reports.  It also prevented printing of the forms. The reason was because .NET 3.5 was not installed by default on Windows 10.  Once I installed that and then uninstalled and re-installed the product update I was able to print.  I may have had to use REGASM to register the a4wcrinterop.dll.

From the knowledge base applies to Windows 10 as well.

• Run command prompt as administrator
• From command line enter this command, C:\Windows\Microsoft.NET\Framework\v4.0.30319\regasm /register [sage300runtimefolder]\a4wcrinterop.dll.
  • where [sage300runtimefolder] is the location where Sage 300 ERP is installed. (i.e. - C:\Windows\Microsoft.NET\Framework\v4.0.30319\regasm /register "C:\Sage\Sage 300 ERP\runtime\a4wcrinterop.dll")
  • modify as necessary (per path to runtime folder)
• If the registration fails, ensure that the Crystal Runtime Engine is installed properly by viewing the files in "C:\Program Files\SAP BusinessObjects\Crystal Reports for .NET Framework 4.0\Common\SAP BusinessObjects Enterprise XI 4.0\win32_x86" (for 32bit computers) or "C:\Program Files(x86)\SAP BusinessObjects\Crystal Reports for .NET Framework 4.0\Common\SAP BusinessObjects Enterprise XI 4.0\win32_x86" (for 64 bit computers).
• For Windows 2012/2012 R2 and Windows 8/8.1, ensure that .NET Framework 3.5 Feature is enabled.

Thanks for the fast and thorough response!  Yes, they are on PU3.  I had trouble registering a4wcrinterop earlier, when the server / workstation setup had been addressed by server name.  So I uninstalled and reinstalled with IP address instead, and this time, there was no error message about needing to register, and the Crystal Runtime files are in place.  But I had not considered .Net 3.5, so I'll go back and try that now.  

FYI, Windows 10 and Sage 2014 has problems with UNC paths to the sage programs server.  This is fixed in the upgrade, you'll see a new "virtual" folder named C:\Sage300Local, which redirects to the server install.

.Net 3.5 was the problem.  Thanks for that tip!

Thanks Jay, for that reminder of new confusion when we upgrade :-)