I have two friends I play with and none of us can get a multiplayer games we have saved to load. We are getting the same error message. Is there a work around or anything? We have tried changing AV settings, opening firewall.

[2021.07.17-03.31.24:207][260]LogPackageName: Error: DoesPackageExist: DoesPackageExist FAILED: 'SB_Name_03' is not a standard unreal filename or a long path name. Reason: Path should start with a '/'
[2021.07.17-03.31.34:531][689]LogRF: Loading a save done on build: t6-#384-win64-gog@0747940
[2021.07.17-03.31.34:634][689]LogRF: BeginPlay map=/Game/Maps/Sandbox/Sandbox_03/SB_Name_03, saveGame=Trop6_Sav_Nido De Iguanas 5y 10 m, netmode=2
[2021.07.17-03.31.37:949][689]LogWindows: Error: === Critical error: ===
[2021.07.17-03.31.37:949][689]LogWindows: Error:
[2021.07.17-03.31.37:949][689]LogWindows: Error: Fatal error: [File:Unknown] [Line: 425]
[2021.07.17-03.31.37:949][689]LogWindows: Error: Pure virtual function being called
[2021.07.17-03.31.37:949][689]LogWindows: Error:
[2021.07.17-03.31.37:949][689]LogWindows: Error:
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ffcabcf4ed9 KERNELBASE.dll!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c48ee6d9 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c49235a8 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c48b13fc Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c487e4bd Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ffca2d76994 VCRUNTIME140.dll!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c40d305a Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c4132e4d Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c40f3385 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c3dfde7d Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c410702d Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c4103cff Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c40e65b6 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c5694dd3 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c55c1287 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c3de3d19 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c3de970e Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c3de978a Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c3df19e9 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ff7c613c0a6 Tropico6-Win64-Shipping.exe!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ffcadf97034 KERNEL32.DLL!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error: [Callstack] 0x00007ffcae202651 ntdll.dll!UnknownFunction []
[2021.07.17-03.31.37:949][689]LogWindows: Error:

I was searching the web for this issue, as a friend and I are also experiencing this exact issue. We basically cannot load any save game created in multiplayer, however single player works just fine.

Since this issue you've reported was back in July 2021, it seems that it hasn't been patched yet and might unlikely happen to be patched at all, making multiplayer sessions impossible to be saved for us. What a bummer.

I wonder why there are no more reports than this, I was searching the web for this issue without finding any clue. Maybe this is caused by specific circumstances. Do you happen to run the game on a AMD Ryzen based CPU ? I do run it on a AMD Ryzen CPU, perhaps this could be caused by the drivers.