I am currently running Mint 17.2 with Qt 5.2.1, which for various reasons I don't want to uninstall. However, wanting to try the latest release, I used the Qt downloader to install 5.8 in $HOME/Qt, as suggested. At the end of the install, it asks whether to run qtcreator; I did and it looked fine. But after exiting, any attempt to rerun gives the message:

Qt Code: 
  1. tonyb@new-laptop ~ $ ~/Qt/Tools/QtCreator/bin/qtcreator
  2. Cannot mix incompatible Qt library (version 0x50201) with this library (version 0x50800)
  3. Aborted
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I get the same result if I run the shell script provided with the binary. I have ascertained that the shell script sets LD_LIBRARY_PATH to:
/home/tonyb/Qt/Tools/QtCreator/lib:/home/tonyb/Qt/Tools/QtCreator/lib/qtcreator:/home/tonyb/Qt/Tools/QtCreator/lib/Qt/lib

I get the follwoing output from ldd:
Qt Code: 
  1. tonyb@new-laptop ~ $ ldd   ~/Qt/Tools/QtCreator/bin/qtcreator
  2. 	linux-vdso.so.1 =>  (0x00007ffd6ffb2000)
  3. 	libExtensionSystem.so.4 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/qtcreator/libExtensionSystem.so.4 (0x00007f9cea939000)
  4. 	libAggregation.so.4 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/qtcreator/libAggregation.so.4 (0x00007f9cea732000)
  5. 	libUtils.so.4 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/qtcreator/libUtils.so.4 (0x00007f9cea365000)
  6. 	libQt5Widgets.so.5 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt5Widgets.so.5 (0x00007f9ce9b34000)
  7. 	libQt5Gui.so.5 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt5Gui.so.5 (0x00007f9ce9398000)
  8. 	libQt5Concurrent.so.5 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt5Concurrent.so.5 (0x00007f9ce9191000)
  9. 	libQt5Network.so.5 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt5Network.so.5 (0x00007f9ce8e0b000)
  10. 	libQt5Core.so.5 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt5Core.so.5 (0x00007f9ce86ea000)
  11. 	libGL.so.1 => /usr/lib/x86_64-linux-gnu/mesa/libGL.so.1 (0x00007f9ce845d000)
  12. 	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f9ce823f000)
  13. 	libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f9ce7f3a000)
  14. 	libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f9ce7c34000)
  15. 	libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f9ce7a1e000)
  16. 	libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9ce7658000)
  17. 	libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f9ce7454000)
  18. 	libQt5Qml.so.5 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/qtcreator/../Qt/lib/libQt5Qml.so.5 (0x00007f9ce6e58000)
  19. 	libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f9ce6c3f000)
  20. 	libicui18n.so.56 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libicui18n.so.56 (0x00007f9ce67a4000)
  21. 	libicuuc.so.56 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libicuuc.so.56 (0x00007f9ce63ec000)
  22. 	libicudata.so.56 => /home/tonyb/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libicudata.so.56 (0x00007f9ce4a09000)
  23. 	librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f9ce4800000)
  24. 	libgthread-2.0.so.0 => /usr/lib/x86_64-linux-gnu/libgthread-2.0.so.0 (0x00007f9ce45fe000)
  25. 	libglib-2.0.so.0 => /lib/x86_64-linux-gnu/libglib-2.0.so.0 (0x00007f9ce42f6000)
  26. 	/lib64/ld-linux-x86-64.so.2 (0x00007f9ceab7f000)
  27. 	libglapi.so.0 => /usr/lib/x86_64-linux-gnu/libglapi.so.0 (0x00007f9ce40ce000)
  28. 	libXext.so.6 => /usr/lib/x86_64-linux-gnu/libXext.so.6 (0x00007f9ce3ebc000)
  29. 	libXdamage.so.1 => /usr/lib/x86_64-linux-gnu/libXdamage.so.1 (0x00007f9ce3cb9000)
  30. 	libXfixes.so.3 => /usr/lib/x86_64-linux-gnu/libXfixes.so.3 (0x00007f9ce3ab2000)
  31. 	libX11-xcb.so.1 => /usr/lib/x86_64-linux-gnu/libX11-xcb.so.1 (0x00007f9ce38b0000)
  32. 	libX11.so.6 => /usr/lib/x86_64-linux-gnu/libX11.so.6 (0x00007f9ce357b000)
  33. 	libxcb-glx.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-glx.so.0 (0x00007f9ce3363000)
  34. 	libxcb-dri2.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-dri2.so.0 (0x00007f9ce315e000)
  35. 	libxcb-dri3.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-dri3.so.0 (0x00007f9ce2f5b000)
  36. 	libxcb-present.so.0 => /usr/lib/x86_64-linux-gnu/libxcb-present.so.0 (0x00007f9ce2d57000)
  37. 	libxcb-sync.so.1 => /usr/lib/x86_64-linux-gnu/libxcb-sync.so.1 (0x00007f9ce2b51000)
  38. 	libxcb.so.1 => /usr/lib/x86_64-linux-gnu/libxcb.so.1 (0x00007f9ce2932000)
  39. 	libxshmfence.so.1 => /usr/lib/x86_64-linux-gnu/libxshmfence.so.1 (0x00007f9ce272f000)
  40. 	libXxf86vm.so.1 => /usr/lib/x86_64-linux-gnu/libXxf86vm.so.1 (0x00007f9ce2529000)
  41. 	libdrm.so.2 => /usr/lib/x86_64-linux-gnu/libdrm.so.2 (0x00007f9ce231b000)
  42. 	libpcre.so.3 => /lib/x86_64-linux-gnu/libpcre.so.3 (0x00007f9ce20dc000)
  43. 	libXau.so.6 => /usr/lib/x86_64-linux-gnu/libXau.so.6 (0x00007f9ce1ed7000)
  44. 	libXdmcp.so.6 => /usr/lib/x86_64-linux-gnu/libXdmcp.so.6 (0x00007f9ce1cd1000)
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Trying the same thing under Ubuntu 16.04 with Qt5.5.1, I get similar output.

Qt Code: 
  1. tonyb@tonyb-SharkBay:~$ /homex/tonyb/Qt/Tools/QtCreator/bin/qtcreator
  2. QXcbIntegration: Cannot create platform OpenGL context, neither GLX nor EGL are enabled
  3. QApplication: invalid style override passed, ignoring it.
  4. Cannot mix incompatible Qt library (version 0x50501) with this library (version 0x50800)
  5. Aborted (core dumped)
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Any ideas how I can debug further?