Some Windows users may find that programs such as Mercury, Mogul, Hermes etc in the 2020.0 CSD Portfolio release and later releases fail to open correctly (the interface may start to appear but crashes immediately). If other programs such as ConQuest launch successfully then this is likely an issue with the graphics system on your computer and the new 64-bit versions of Mercury, Mogul & Hermes.
This issue should be resolved with the 2020.0.1 patch release of the CSD Portfolio (i.e. Mercury 4.3.1 etc), so the first suggestion is to ensure you are using the latest version (2020.3 at the date of writing)
If upgrading to the latest release does not help or you are wanting to get the 2020.0 release (Mercury 4.3.0) working, then the first suggestion is to delete the Qtshadercache on your computer - this is a set of information that Qt (the technology that we use to create the interfaces that Mercury etc use) saves to your computer. An incompatibility can occur between the information saved from our older 32-bit software in previous releases and the new 64-bit versions in the 2020.0 release.
The shader cache can be found in %UserProfile%\AppData\Local\cache\qtshadercache on your computer. Delete this and that should hopefully get the CSD software running properly.
If that does not help, the next step is to ensure that your graphics system's drivers are fully up-to-date. We would recommend downloading the latest drivers direct from the graphic system's manufacturers website (e.g. Intel, NVidia, AMD etc).
Lastly if the above steps do not work, please start Mercury by double-clicking on the "mercury_with_logging.bat" file in the Mercury folder of your installation. This should create a log file in your user home area - please forward this on to firstname.lastname@example.org with full details of the issue and the version of Windows you are using.