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How to find lost license keys and serial numbers for apps on Windows 10

Paid software authenticates a user in one of two ways; a license key or a serial number that is given at the time of purchase or by having the user sign in to an online account that was used to make a purchase. 

Both methods have their own advantage. Authentication through an online account means you only need a username and password to verify a purchase. If you forget either of them, they’re easy to recover.

Authentication through a license means you don’t have to be connected/online in order to activate and use an app. With this method, though, you must keep your license key or serial number safe.

Find lost license keys and serial numbers

A license key or a serial number for an app is lost when you install Windows 10 fresh, and sometimes it may be lost when you uninstall and reinstall the app itself. Bugs within the app can also end up removing a license.

If you’ve lost a license key for an app, but the app is still active, and you want to recover its license/serial number, you can do so by looking through the Windows registry. It’s not easy, though since the registry is huge, which is why we recommend using an app called LicenseCrawler.

Recover lost license keys & serial number

  1. Download and install LicenseCrawler.
  2. Run the app and do not change the default settings.
  3. Click Start Search.
  4. Allow the scan to finish.
  5. In the pane on the bottom, go through the various apps and keys that LicenseCrawler has found.
  6. Copy the keys you want to save to a Notepad file, encrypt it, and keep it somewhere safe.

Note: this app can also find your Windows 10 license key.


Paid or premium software doesn’t always rely on a serial number or license key, even when it doesn’t use an online account to authenticate a purchase. To fight software piracy, apps use all sorts of different methods to check a license. 

Some licenses aren’t numbers. Instead, they are LIC files that are executed and read by an app to authenticate a purchase. LicenseCrawler cannot find these types of licenses.

If you’ve already done a clean install of Windows 10, or you’ve uninstalled the app you’re trying to recover a license for, LicenseCrawler will not be able to help you.

LicenseCrawler is free for end-users, but you will run into quite a few annoying windows that will have to be dismissed when you use the app. 

Recovering other types of licenses

For licenses that LicenseCrawler is unable to find, you should comb through your email. Often, developers mail the license or license file to users over email. Check the email account that you used to make the purchase.

If you’re unable to find a license in your email, you can also try to get in touch with the developer. Let them know you’ve lost the license key, provide them with the email you used to purchase a license, and the date you made the purchase on. In many cases, developers will be able to issue a new license or send you your old one for free. 

Keeping licenses and serial numbers safe

Once you’ve recovered a license key or serial number, your first priority should be to keep it safe so that you can find it later. 

When saving the information, make sure that it is secured, e.g., the information should not be lying on your desktop in a plain text file. If it is in a text file, upload it to a cloud drive, where you will first have to sign in before you can access the file.

If you use a cloud drive to save a license or serial number, make sure that the cloud drive isn’t syncing the information to your desktop. This makes the information easy to steal.

Make sure the information isn’t stored locally or that it is stored elsewhere in addition to being stored locally. If your hard driver or SSD fail, or Windows 10 is corrupted, you don’t want to lose access to licenses that you’ve recovered simply because you saved them in the wrong place. 

Licenses may or may not be transferrable i.e., a license can be limited to working only on the system it was originally used on, and not on others. In that case, you may have to purchase a new license to get it to work on a new/different system.

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