Both the Installed and Portable versions of Hard Disk Sentinel Pro are (in terms of licensing and functionality) same: they are both Professional versions and they have 100% same functions, features. The only difference is how the software used (installed OR launched from a removable device, eg. pendrive/CD) and started (automaticaly on startup OR manually).

So generally, if you have one license for Hard Disk Sentinel Professional, you can decide if you prefer to use
- with the Installed version (to get real-time protection)
OR
- with the Portable version (to use by a pendrive, without installation to diagnose / fix issues)

A second (additional) license would be required only if you'd prefer to keep the installed version on a system - and use an other license in addition with the Portable version to check/diagnose/repair issues on different systems wtihout installation.

If you prefer to use Hard Disk Sentinel Pro Portable:

1) download the latest Portable package from
https://www.harddisksentinel.com/hdsentinel_pro_portable.zip
and extract to a new folder on the removable media (pendrive).

2) start HDSentinel.exe from the folder where you extracted the package.
In the Help -> About box, you can verify that it is the portable version, the word Portable should be displayed there. (If you have the installed version on this system too, you'd need to first close it completely by File -> Exit before starting the Portable version as only one instance can be running at any given time).

3) Please click on Help and select Enter registration key in Hard Disk Sentinel Pro Portable

Please enter your name (or nickname) as username, the license code you have (15 digit number) and click on the Register and activate on-line button. Then the software should be registered and activated and can be used without limitations.

Make sure that the software need to access the activation server during the activation, so your firewall should not block it. Then the license will be active for the Portable version on your pendrive.

If you prefer to keep the installed version, then you'd need a second (different) license or the most economic solution is to upgrade the Professional license to Professional Family license, which can be used on up to 5 computers (or 5 pendrives - or any combination of them, eg. the installed version on 4 computers and the Portable on 1 pendrive).