Activation Help

This guide attempts to clear confusion about various activation errors, and outlines specific workarounds applicable to each case. If your problem still occurs, feel free to contact us.

Please Note: The activation mechanism is not 100% accurate. Sometimes, genuine users may receive an error that they really shouldn’t. Feel free to drop us an email for any help you may need with the activation process.

Invalid or Expired License Key

The activation key you’ve entered is either invalid or it has been expired.

1. Verify your key: Please verify your key. To avoid typos, copy it directly from the email you received after your purchase.
2. Check license expiry: Make sure that your license hasn’t expired.
3. Update DupInOut Duplicate Finder: Are you trying to activate the license key on a very old, unsupported version? If so, it may not work. Please uninstall your current version, and manually download & install the newer version from the official download page. Avoid the built-in Update Checker, as it may fail with very old, unsupported versions.
4. Giveaway promotion offer has ended (Use the offline activation method instead): You activated a 1-Year free Giveaway license key on January 2026, and then formatted your machine on February 2026. Subsequently, you were unable to re-activate your license. Technically, your license hasn’t expired, so the key should have worked. However, as the Giveaway promotion offer has ended, the activation server will no longer be able to validate your key and an error will occur. The solution? Simple: Use the LICENSE.DAT file provided in the original Giveaway zip file to re-activate your license offline.

License Key Version Mismatch

The activation server reported that the license key entered is not associated with this version of the product. Some license keys come with limited years of updates. If your license doesn’t permit upgrading beyond a specific year, the key will no longer work on the newer versions.

1. Check whether you’re allowed to upgrade (you had opted for a limited updates plan): Please check your purchase email. If applicable, consider downgrading to the supported version.

Device Fingerprint Mismatch

The activation server has responded that the entered activation key is valid. However, it is already tied with a different machine or the hardware of your computer has significantly changed (for example, you recently upgraded multiple major hardware components).

1. Enter the correct key tied to your PC: Do you use multiple computers? If so, if you had activated “Key 1” on “Computer 1”, it will be tied to that specific machine. You won’t be able to activate this key on “Computer 2” or “Computer 3”. The solution? Just try to recall the correct key you used on this machine before.
2. Your computer has undergone significant hardware changes: If you’re recently upgraded a large chunk of your computer hardware, a fingerprint mismatch could occur. No worries! Just drop us an email to unlink your previous device. Once we unlink it, your key shall continue working.

Unable to Contact the Activation Server

This can be a frustrating issue as the root cause is mostly unknown. It could be your security software blocking communication with the activation server. Or you’re trying to activate a very old version of DupInOut Duplicate Finder. Or it could be a third-party technical issue, especially if you’re using an older Windows version. Unfortunately, there’s no easy way to figure it out.

1. Check network connectivity: Make sure you’re connected to the Internet.
2. Update DupInOut Duplicate Finder: Make sure you aren’t using an obsolete unsupported version. Please uninstall your current version, and manually download & install the newer version from the official download page. Avoid the built-in Update Checker, as it may fail with very old, unsupported versions.
3. Temporarily pause your security software: Temporarily pause your real-time protection feature and try activating the software. After successful activation, don’t forget to re-activate your device protection!
4. Request offline activation file (LICENSE.DAT): If you’re a paid customer, drop us an email requesting the LICENSE.DAT file for offline activation. This method will entirely bypass the need to connect to the activation server.

Invalid Response from the Activation Server

The activation server responded with an unpredictable text.

1. Update DupInOut Duplicate Finder: You’re likely using a very old, unsupported version of the software. Please uninstall the current version, and manually download & install the latest version from the official download page. Consider avoiding the built-in Update Checker, as it may fail with very old, unsupported versions.

Your Previous Activation or Trial Status Could Not be Retrieved

In most cases, this is only a temporary error. The software failed to retrieve your previous activation or trial status.

1. Close and re-open the software: Simply close DupInOut Duplicate Finder and re-open it again. It will automatically retrieve your last activation or trial status.