I'm using Ubuntu 15.10Problem:For some days now I have been getting Errors like this when opening some applications:  /usr/lib/x86_64-linux-gnu/libpoppler-qt5.so.1: undefined symbol: _ZN6QDebugD1EvSome applications affected aretexstudio shows/usr/lib/x86_64-linux-gnu/libpoppler-qt5.so.1: undefined symbol: _ZN6QDebugD1EvIPython's qtconsole shows/usr/lib/python3.5/site-packages/PyQt5/QtCore.so: undefined symbol: _ZNK12QStorageInfo11displayNameEvkonsole (KDE's terminal emulator - I'm using Unity though) shows /usr/lib/x86_64-linux-gnu/libKF5ItemViews.so.5: undefined symbol: ...granatier (a KDE game), KSysguard and KAddressbook also show errors in KF5 librariesalso failVLC seems to be affected too since it says there is something wrong with Qt 4 (see below)Qtall of this errors seem to come from Qt linked libraries (Qt appears in most filenames and most symbol names). AFAIK KDE ist baed on Qt, which would explain why all KDE applications fail.It seems to affect both Qt 4 and 5Possible OriginThe day this problems appeared I had enabled wily-proposed packages in the Ubuntu Software &  Updates System application. I interrupted the upgrade and tried this to roll it back.  After this I had a similar problem with ssl but it went away eventually.
Symbol lookup errors in (Qt?) dynamically linked libraries
ubuntu;package management;kde;dynamic linking;qt