Windows 7 64-bit: icon does not appear on taskbar

I had this problem with a CCleaner icon. It would be pinned, but be the blank unknown application icon. I just removed it and tried again. Worked second time. Don't know why!

"There is a solution posted at a Microsoft forum:

First phase

Click Start
Right-click on Programs in the Start menu
Select Properties ⇨ Shortcut tab ⇨ Change Icon ⇨ Browse
Navigate to the .exe file for this program and select it
Select an appropriate icon from options shown (if you get a message saying only an administrator can do this, click continue to apply the change.)

Second phase

Start a session of the application
While it is running, right-click the taskbar button
Select Unpin this program
Right-click again (shows icon now because it represents the running app, not the shortcut)
Select Pin this program"

"Just Do this simple trick and it will work.

change momentarily the screen color depth to 16 bits and when Windows asks you whether you want to keep the changes or not, click ""No"" to restore the original settings.

Then Pin the Icon, it should work"