>>>An app has a function to save VFP data as a .XLSX file. The code below is 100% reliable on machines running Excel 2007 on Windows 7. On some machines with Windows 10 and Excel 2016, it fails when a call is made for Excel to open the FOX2X file.
>>>
>>>Does anyone have any ideas why Excel 2016 and/or Win10 might not like this code?
>>>
>>>

>>>* Get Excel application object:
>>>m.loExcel = CREATEOBJECT( "Excel.Application" )
>>>
>>>* Data munging to create a VFP cursor happens here
>>>
>>>* Save the cursor to a FOX2X file that can be opened by Excel:
>>>m.lcDBF2X = ADDBS( SYS( 2023 ) ) + SYS( 2015 ) + ".DBF"
>>>
>>>COPY ALL TO ( m.lcDBF2X ) TYPE FOX2X
>>>
>>>* The following DOEVENTS call "fixed" OLE errors long ago with Win7/Excel 2007:
>>>DOEVENTS FORCE
>>>
>>>* Open the FOX2X DBF in Excel, save to .XLSX format:
>>>m.loExcel.DisplayAlerts = .F.
>>>
>>>* The next line is the one that throws errors:
>>>m.loWorkbook = m.loExcel.Application.Workbooks.Open( m.lcDBF2X )
>>>

>>
>>type fox2x creates a foxpro 2.x compatible file, not an excel file. Instead use VFPOLEDB. Check message #1650041
>
>Yes, I understand that. As noted in my comments, historically Excel has been able to open FOX2X files as "dBASE"/.DBF. They can then be saved as .XLSX files. I'd like to find out why this process is unreliable on Win10 and newer versions of Excel.

It now too would open using jet or ace engine driver. The error code you get indicates that it is a security issue (access denied code).