Hi stuartg,

There could be many causes to this. As you say, it's possible there may be a conflict between multiple running instances of ppalambic. A possible scenario would be two instances of alambic trying to call the same external image. When an external image is accessed, it may become locked, and if another instance tries to access it at the same time, it will cause an error. As for it not happening in 5.3, the handling of threads is completely different in 7 than in 5.3(I believe Image 5.3 wasn't multithread at all...), so this issue might not have existed in the previous version.

Just to be sure: you ain't still running 5.3, right? Running both versions of the services on the same system at the same time isn't supported, and WILL cause issues, if you even succeed in starting them both together at all.

Regards,
Raphaël Lalonde Lefebvre