Is there any way of resolving this problem: In Solidworks 2019 I have just finished an assembly that took about 50 hours to design. Once the design was finished I have exported a Step file and afterwards I did a Pack and Go Zip save on my backup external disc. Upon opening the assembly from the zipped folder I saw all the virtual components were missing from the assembly. I went back on the primary disc to open the original file and the same thing happened. Now, still before the file is fully loaded I can see the full assembly (screenshot 1), but once it fully loads all the virtual components go missing and a warning about missing mirror planes appears (screenshot 2).

I would greatly appreciate any help!