LEAD Multimedia Library Eval Notice pops up in some deployments

My company has been using LEAD libraries for photo capture for about a year now with no issues. We have a serial number and distribute DSKernal2.dll (1.0.0.60), ltmm15.dll (15.1.0.2), and a ltmm.lic license file.

We unlock the library by calling LMDSKernel2#unlockModule with our serial number, UnLockFlagsConstants2.UNLOCK_APP_ALWAYS, and a GUID we generated.

This works fine in most of our 3000 installation sites.

However, recently, a small number of sites have been reporting that the evaluation message appears and they are locked out from capturing photos. The message reads Title: "LEAD Multimedia Library (15.1) Eval Notice", Body: "The evaluation period has expired. Please contact sales@leadtools.com to obtain a release version of the filter." with an OK button. (See attached screenshot).

These sites are  running the exact same code and unlocking the files in the same way. We have verified that all the files we require are present.

What controls when this eval notice is shown?
Can another vendor install an non-compatible version beside our application and cause this?
How can we get rid of this message? Our code and deployment works at 99.6% of our sites, but breaks on about 1 of 300.

On one of the machines that have the problem, please re-register the LEAD DLLs from the locations where you deployed them. This should be a common folder such as SYSTEM32 or SysWOW64 on 64-bit machines. This will rule out some other application registering our DLLs in a different folder.

If the problem is not solved, try to log on using an administrator account and re-install the application, then use the application using the same account (same user credentials). This will eliminate possible problems due to restrictions imposed on the account itself.

Following this advice simply isn't an option in our deployment scenario. There would be a great expense to reinstalling this stuff on site.

I was able to reproduce the issue by running two instances of the application. When two instances are running, the second one displays the trial license expired message.

I am unlocking the DLL using UNLOCK_APP_ALWAYS : http://www.leadtools.com...enumerationconstants.htm

If I change to UNLOCK_APP_ONCE, then multiple instances can run on the same machine.
If I use UNLOCK_APP_ALWAYS, but generate a unique UID for the application ID, then multiple instances can run on the same machine.

The behavior of the unlock flag seems backwards. Shouldn't I be using unlock always with a single UID? What flags should I be using here?

That depends on what you're actually unlocking.  The main Multimedia SDK can ONLY be unlocked with UNLOCK_APP_ONCE.  The other flags such as UNLOCK_APP_ALWAYS  and UNLOCK_COMPUTER will only work for stuff like the individual filters or codecs.