Man, do I hate when weird, mysterious, obscure bugs insists to randomly strike when you're expecting them the least. (1)
I turned on my personal computer this evening, only to face this:
That's it. No desktop.
Every single program I invoke runs in fullscreen mode. Including the Calculator (and it's awful). Their windows have no minimize and restore buttons, only the close button.
Right-clicking what was supposed to be the taskbar reveals these three options:
Which suggests me that maybe Windows thinks I'm on a tablet. And I'm certainly not.
A few troubleshooting points:
- It's a rather standard Windows 10 (ver 10240) installation, SSD-based, Bitlocker enabled. Windows Defender disabled by group policy. It has worked well for more than a year.
- The system was last turned off this morning, via
shutdown /s /t 0(I do that once every a few days to keep everything fresh).
- I don't have the habit of using system cleaning tools, such as CCleaner. Definitely not related.
explorer.exeis running, and so is
dwm.exe. Windows explorer can be invoked by Winkey + E and works - but it's unusually slow.
- Restarting the OS didn't fix it.
- It also happens in Safe Mode.
- Nothing unusual in Task Scheduler, or in the Startup entries.
- It might be malware. I ran this utility earlier yesterday, and I don't use any antivirus at all (only used Outpost Firewall/Hips, but it's license expired). It was an act of imprudence, I know. But a preliminary analysis using Sandboxie didn't reveal anything wrong with that file.
Just what the heck is going on Can someone shed a light on this puzzle?
- When I open the Task Manager
Detailtab, two instancies of
dllhostshow up, and then disappear in a matter of seconds. It happens everytime. The instancies always have different PIDs.
- A similar thing happens in Process Hacker x64 - but only for the first time it's launched. And only one
dllhostinstance, instead of two.
- I created a new Administrator account, logged in, and the desktop is normal in there.
- "Use Start full screen" is disabled in Windows 10 Personalization Settings.
- Winkey + D, Winkey + M or Winkey + X + clicking "Desktop" does nothing.
(1) See here for another example (yet to be unraveled).