Sharing this in case anyone else has this problem.
After upgrading to OS5 on MYCloud EX2 Ultra could still be seen on the Network in Windows 7 Explorer but attempts to open or map the drive resulted in an error. First sign of a problem was Acronis backup started to fail. It still worked fine on Windows 10. I tried several things I found on the internet to fix the problem from the Windows settings but none of them made any difference. I finally looked at the Network settings and decided to downgrade the SMB protocol to include 1, 2 and 3 and the NT LAN Manager to include v1 and v2. I tried this because several of the windows side solutions included changing these settings through policies, network device settings or registry edits. I did not change the windows settings back to their original settings so I don’t know for sure whether it was in combination with the settings I changed in Windows or just the NAS settings that fixed the problem.
Really annoying that the Upgrade “ads” do not inform you about compatibility with Windows 7. Before anyone comments about MS win7 support, I have software that will not run on Windows 10 so I have not upgraded this one PC from win7 to 10.
