Joplin GUI does not appear

Hi! Help me troubleshoot a problem. I am running 1.2.6 under Windows on two computers, and synch the data between them using DropBox. Computer A works find. DropBox synchs to both Computer A and Computer B. However, on Computer B, when I start up Joplin, the GUI never appears. The processes show a running Joplin process with 3 sub-processes using 20% of CPU. I am unable to provide more information about this error because the GUI never appears. I can't bring up the GUI to set any debugging options. The only differences that I can note is that the non-functioning Joplin runs under Windows 10 Pro while the functioning one runs under Windows 10 Home; also that the non-functioning machine is an HP machine while the functioning one is home-built.

What is my next step? Thanks for your help.

Joplin for Desktop
Copyright © 2016-2020 Laurent Cozic
Joplin 1.2.6 (prod, win32)
Client ID: 348634c19a984fbc80460ee0b23c7d45
Sync Version: 2
Profile Version: 34
Keychain Supported: Yes
Revision: f5f117cb (master)

Others have had the situation where Joplin is running but not within the screen boundaries. Could this be your problem?

Thanks, but no luck. It was worth checking though. I've seen the "off-screen" type of issue before, and in those cases, I could right-click the running task in the task bar, but for my issue, I never get that icon.