Major issues with upgrade to version 5

[Efcis]

This excellent FAQ post can also probably help you:

Converting KiCad version 4 projects to version 5 (Remap a project)

Disclaimers Remapping a project will mean that it can no longer be opened with version 4! No matter what you do always make a backup first. (One should always do that before doing major changes. It also makes it easy to restart should the result be different from what one expects.) 5.1.2 has a bug where it sometimes shows question marks for symbols even with them being ok. Restarting eeschema will fix it if the bug is to blame for having question marks. Remember to save before restarting (You …