Pinned apps on taskbar are missing until repinning or restarting Explorer

My Dell Inspiron 5558 has been updated to Windows 10 Creators Update. Few days after updating, pinned apps on the taskbar disappeared. I have been trying fixing this weird behavior by doing some workarounds:

• Repinning one of the apps. All the pinned apps appear, but after the laptop restarts, they are gone again.
• Restarting Explorer. Same behavior as above.
• Using sfc /scannow in an elevated Command Prompt. It completes successfully, but it does not find any violations.
• "Upgrading" Windows using Media Creation Tool. It looks like the problem has been fixed, but after some system reboots, the problem returns.

I have also tried the following fix. Things have become interesting.

I download installation ISO file from Microsoft website (not via Media Creation Tool), mount it and then use dism in an elevated command prompt:

Dism /Online /Cleanup-Image /RestoreHealth /Source:wim:D:\sources\install.wim:1 /LimitAccess

where D: is the virtual drive created after mounting the ISO.

• First try: The command does not finish. It shows the error code 0x800f081f with a message The source files could not be found. I check the logs and find that Dism stops at Microsoft-Windows-TestRoot-and-FlightSigning-Package~31bf3856ad364e35~amd64~~10.0.15063.0 which is a problematic package. I have removed that package, like this post instructs.

• Second try: The command finishes successfully. But after restarting Windows, pinned apps still do not show on the taskbar.

Before removing that package, I tried running the following Dism commands, and they also nearly finish with error 0x800f081f:

Dism /Online /Cleanup-Image /RestoreHealth
Dism /Online /Cleanup-Image /RestoreHealth /Source:wim:D:\sources\install.wim:1
Dism /Online /Cleanup-Image /RestoreHealth /Source:esd:D:\sources\install.esd:1
Dism /Online /Cleanup-Image /RestoreHealth /Source:esd:D:\sources\install.esd:1 /LimitAccess

A very interesting thing is that the problem does not appear when I get into Safe Mode. I try removing video drivers, then reboot and return to normal mode to have those drivers downloaded and installed automatically from Windows Update. But when I return to normal mode, the problem is still there.

UPDATE: I have tried uninstalling all drivers and apps that I have downloaded from Dell Support, and then let Windows Update install drivers for the laptop. The problem is gone, but only when I turn off the laptop completely and then turn on again. The problem still exists when I just perform a restart command.

Is there a permanent fix to this problem? Or, do I have to wait for a new update?

I have found the cause of this problem. It is Ransomware Protection module of BitDefender 2017.

When I turn on Protection at boot, BitDefender's service makes the hard disk too busy on reboot, leading to the temporary disappearance of pinned apps on the taskbar. The problem has been known for some time.

After updating BitDefender, the problem is now gone.