This occasionally happens to me with some icons in my System Tray. After much checking, I had no viruses, malware or corrupted Window files to blame the occasionally missing icons on. My solution was to simply open Task Manager, click on the process associated with the missing icon (mbam.exe*32 in the case of Malware Bytes), then click on End Process. Then go to Start, Programs, and click on the program you just ended. The program will start, and the icon will appear in the System Tray. Or at least it works that way for me... I find Ending Process (via Task Manager), and restarting the program much quicker than rebooting the computer... Hope this helps, Jim