It is not always obvious what process is currently using a specific port. This can make identifying why a Qlik service is not starting difficult.
This is how you find what task that is currently listening on the default HTTP-port 80 or HTTPS-port 443. This can be applied to any port.
Open the Command Prompt (cmd.exe) and execute the following:
Step 1 - Find PID of program:
netstat -ano | find "443" or netstat -ano | find "80"
The list could be long. Look for something ending with :443 or :80 in the second column. Get the pid from the right most column (e.g. 37400)
Step 2 - Find the name of the task with the resulting PID:
tasklist /svc /FI "PID eq 37400"
The output should give you the name of the task that is blocking your port.
Step 3 - If the PID turns out to be PID 4 or something else that displays "Can not obtain ownership information" use:
net stop http
This will show you any additional services that are dependent on 80/443
