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You can activate rekordbox dj in up to two computers with one license.
Please note that the same rekordbox user account is required for the two computers if you activate rekordbox dj with one license.
You can activate it by following the instructions below.
When you launch rekordbox for the first time after installing it, the following window automatically appears. Click [Activate a license key] and enter your rekordboxdj license key to activate it .

If it is not the first time you launch rekordbox dj after installation, open [Preferences] > [License] > [rekordbox dj], click [Activate] and enter the license key to activate it.

If you do not revolve the problems, please file a rekordbox inquiry here and our support team will be happy to assist you with this issue.