What I have done in the past for using multiple computers to work on the same project was as followed.
use the same editor version (which you seam to be doing)
be sure the entire project is accessible from the folder it was made in (which you seam to confuse me on what exactly your doing)
throw the project to the editor, do this by opening the editor from the project select screen, and then selecting the .uproject from the editor file select.
Try this with the project on an external drive
be sure that you just copy the entire project folder on to the drive, and don’t leave behind any content material.
now you seam to be doing this, but if you could provide some images, maybe I could get some details about the issue not described.
what happens when you try to open it? is there a crash? does it do anything? does it ask which version to use? if it appears to do nothing did you try checking the task manager to see if its running in the background? how long did you leave it?
I transferred my complete project folder to my flashdrive. I then copied the folder to my new PC. It seems that the *.uproject file doesn’t transfer properly. I need to choose an app to open the file and I chose unreal engine and it still doesn’t work.
solved - I transferred my project from my work laptop so the files were encrypted. Once I saved it on google drive it went fine. thanks for your help anyhow!
