@maik I assume you installed it using the MSI, is this right?
When you update it using the MSI, do you also need to run the Deployment tool to individualize it, or is that only a deployment step? i.e. can you just run the msi as msiexec Snagit-newversion.msi /qn /norestart?
And do you know how it deals with the license, if you upgrade the major version?