They'll work fine together, but if you have Explorer thumbnails enabled, the behavior there could be strange. I'm pretty sure the Explorer thumbnails feature will use the version of LDView that has been run most recently. So, if you run LDView 4.1 to view a model, then browse to a directory containing LDR files, Explorer will generate thumbnails using LDView 4.1. If you then run LDView 4.2 to view some other model, Explorer will then generate thumbnails using LDView 4.2.
So, if you are experiencing crashes in LDView 4.2, it might be best not to have the Explorer thumbnails feature enabled. Note that unless you know how to use regsvr32 /u, the only way to disable the thumbnails feature is to uninstall LDView. (You can then reinstall LDView with that option disabled in the installer.)
So, if you are experiencing crashes in LDView 4.2, it might be best not to have the Explorer thumbnails feature enabled. Note that unless you know how to use regsvr32 /u, the only way to disable the thumbnails feature is to uninstall LDView. (You can then reinstall LDView with that option disabled in the installer.)