Hasselblad H5D-50c

Have you tested, if only the Hasselblad photos are causing the crash by importing into a new, empty Photos Library?

You could also test in a different user account, to exclude the possibility that older preferences files in your user account our causing the problem.

I have not seen any reports about the Hasselblad in these forums.

But for RAW problems with other cameras it helped to reinstall the RAW support for the camera.

If the problem has really been caused by the recent RAW upgrade, it should help to revert to the last RAW support version that worked for you, but that requires to remove files from the System library.

Search for the last RAW Support versions at Apple - Support - Downloads

For example, Digital Camera RAW Compatibility 6.04

To reinstall:

Make a backup of your system and try to downgrade the RAW support to the before-Yosemite version.

To downgrade the RAW Support to the last version from before the Yosemite upgrade try this:

To reinstall the 'RAW Compatibility Update' it is necessary to uninstall the currently installed raw support. Otherwise the installer will rightfully say, that you already have the latest version installed.

The RAW support files are installed in the System Library in the folder "/System/Library/CoreServices" Folder:

• To open this folder, use the Finder's "Go" menu. Click the smiling Finder icon in the Dock to bring the Finder forward.
• Then type the keyboard shortcut ⇧⌘G (for "Finder > Go > Go to folder") and copy and paste "/System/Library/CoreServices"into the text field. Click the "Go" button.
• In the Finder window that will open, delete both the files "RawCamera.bundle" and "RawCameraSupport.bundle". You will have to enter your Administrator password. (don't empty the Trash, so you can put the files back, if need be)
• Download the current RAW support update or a previous version that supports your camera version from Apple's Support Site:

Digital Camera RAW Compatibility 6.04

Then run the installer.

Does this exclude a raw support problem (since this is shared between users?) and instead would point towards a preference file issue? But why then did I see crashes with both the Photos and Aperture apps

You may have installed third-party applications for RAW development for your user account only.

So the conflicting preferences might be the preferences files for a third-party application - a plus-in or similar. Are plug-ins installed for your user account only, that may no longer be compatible?

If I delete the preference files what settings will be lost in Aperture and Photos, respectively.

This will erase any preference setting, that has been set from Aperture > Preference or Photos > Preferences.

Also, the applications will no longer remember the location of the photo library you last opened and you need to open the library by double-clicking it, to point Photos or Aperture again to your library.

i Forgot mention a further test to see, if system extensions you installed with older software are causing this.

boot your Mac into Save mode. That will disable non-standard system extensions. Aperture usually will not work this way, but Photosor iPhoto might.

if you can work in safe mode, it indicates incompatible third-party software.

That is Safe Mode -- OS X Yosemite: Start up in safe mode

and it not only is a good test but often actually repairs the problem

LN