To be honest it is a first time the VintageWarmer locks a Wavelab.
There are some things that may be a reason of the problem.
Do you use a DX or a VST version under a Wavelab? We strongly recommend to use a VST version in VST compatible host applications.
It is also possible that buffer settings in the Wavelab are too short or too long. I cannot say what settings could be wrong because with most audio drivers buffer settings have nothing to do with the VintageWarmer behavior but on some systems we noted that for instance very short buffers may cause some problems.
Regards,
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Mateusz Wozniak
PSPaudioware.com