Yeah I used to have many versions, some based on purchased, some from old free version, different updates for each and some where duplicates with various plugins installed, then theres the dx10 version and now open source - the size on disk soon builds up but this was on an old machine thats gonna cost more to repair than getting a cheap machine which is exactly what I have done. These days I just have what I need, so only a few versions but if I test for reasons such as this thread I still keep them installed as this is a new machine(new to me - its an old model), so disk space isn't an issue, for now lol. Anyway I have just tested with open source version (no upgrades as then it would no longer be the open source version - I have yet to test if overwriting open source with upgrades throws up any issues but probably won't test any time soon), as you suspected it does not play nice at all, some demo's work but many do not, at least one worked but threw errors before resuming and still appeared to work regardless, but if just one crashes then the whole thing is pointless to me which is the case. U7.7RC7 seems to work just fine. The open source version is U7.1, if I get chance later I may test the purchased version with U7.1 and DD to see if that is possibly part of the reason, although knowing that won't change things - but hey I do get curious a fair bit!.