Protection code is checking integrity of protected application during decryption process. This message is displayed in case application is not properly decrypted.

There are few possible reasons for this:

1. Program has been externally patched (changed), damaged or infected by virus.

2. Remote protection: decryption key is not valid (most common reason).

- Be sure to use the same Program ID for applications with same Application signature.

- Be sure to use correct project for calculation of activation codes.

If you have two applications with same application signature and different Program ID installed on same computer, one of them will be wrongly decrypted and will display "File damaged!" warning message. Both application are sharing the same license data including Program ID (encryption key) and this is why one of them will be wrongly decrypted.

If "Reset license if crc errors are detected" option was enabled in remote protection settings protected application will display "File damaged!" error message and reset current license so that new site/mid code is generated on next run. At this point you can generate new, valid activation code and pass it to your client.

In case this option was not enabled there are two ways for getting out of this situation:

A) License removal feature is enabled:

Instruct your customer to remove his license and provide new site/mid code (which are generated after license removal). Use the latest project settings to generate new activation code.

B) License removal feature is not enabled:

- Enable "Reset license if crc errors are detected" option and protect your program again. Send newly protected program to your customer. This release will reset license and generate new site/mid code so you can generate valid activation code.

3. Program is changed during loading process.

This is done by OS and can not be avoided. You should turn off some encryption (code/data) options until this message goes away.