Find out how long an application has been up and running with the Windows Registry

First, let’s open Registry Explorer (beware it’s an install link) and load the NTUSER.DAT hive. Depending on your case, you can keep the dirty hive.

Let’s dive into this folder : Software\Microsoft\Windows\CurrentVersion\Explorer\UserAssist\.

From now, we can see some GUID folders, some can be empty. Let’s take a look inside of them and search for the name of the application in the search bar (Program Name field).

Now check on the Focus Time column and you’ll get how long an application has been up and running

Video that helped me to learn this new trick here !