Hi, orthnac build depends on libdcmtk-dev, and this pulls in libssl1.0-dev (since dcmtk (a) does not yet support openssl-1.1 and (b) it is used by programs that require QT which conflicts with openssl-1.1). libssl1.0-dev conflicts with libssl-dev, and hence the build failure. The solution is to remove libssl-dev from the build dependencies, since libdcmtk-dev already takes care of pulling the right version in. Best, Gert