In some cases, for example, deleting large trace files, you need to disable the application self-defense.

 In order to disable the application self-defense, perform the following actions: 

• open the main application window 
• in the right upper corner click the Settings button
• in the left part of the Settings window select the Options item
• in the right part of the window uncheck Enable Self-Defense 
• in the right lower corner click the OK button 
• close the main application window.