I came across this problem and finally got it solved manually and I hope this can be seen by whoever faces similar situation and save your time. Here is what I experienced: I tried to open a Unity project from a network shared folder and the editor did not launch correctly (I did not know that it was BY DESIGN NOT SUPPORTED at that time) I closed Unity Hub as usual I tried to launch Unity Hub at another time and got the error message saying UNITY HUB ENCOUNTERS A CRITICAL ERROR When I tried to quit and re-launch Unity Hub, it just gave me a blank window and it does not start When I check Task Manager, there are 2 or 3 Unity Hub tasks there stuck that I could not end task without doing a restart or logout. So I read the log and I saw: Failed with ipc error type: PipeIsNotOpen, Failed to connect to pipe: 'Unity-LicenseClient-[myname] Failed with ipc error type: PipeIsNotOpen, pid: undefined Failed to start Unity Hub, reason: Error: UNKNOWN: unknown error, open '\\\\\\\\Device\\\\Directory\\\\Directory\\\\UnityProjectName\\\\hubInfo.json'\ If you wonder where the log is located: C:\Users\yourusername\AppData\Roaming\UnityHub\logs\info-log.json And here was what I thought: Unity Hub has somewhere to store its recent opened Unity Project list and Unity Hub failed to open it for any reasons (e.g. the disk is disconnected, the shared folder is disconnected, etc.). And that cause the critical error that stops Hub from launching. Solution Open Registry Editor (search it in your start menu) Find the folder called HKEY_CURRENT_USER/Software/Unity Technologies/Unity Editor 5.x Find RecentlyUsedProjectPaths (Be informed that there can be multiple if you have many projects on your Hub's list Double click or Right Click/Modify to see its path which matches the one that caused the error and delete it Try to launch again, if it does not work, re-install Unity Hub too. Why I consider this as a bug although I found it was by design not supported to open projects on network shared folder: It does not matter what it supports or not, it matters that Hub crashes if it cannot find or read a JSON file from a disconnected path. Like there are countless softwares out there that has "Open Recent" option in their File Menu, missing file should not lead to a critical error.