Does anyone know why I crash when opening a note card

[Rolig Loon]

No, but this is reminiscent of an old bug, cured about a year ago when LL brought out viewer 3.4.1.  It's unlikely to be the same problem now, but it's similar.  The problem then was incompatibility with Microsoft's Sky Drive (or the Amazon equivalent Cloud Drive).  If nobody else here has a good idea, you may want to submit a JIRA report and perhaps refer to that old bug.

[Rolig Loon]

No, but this is reminiscent of an old bug, cured about a year ago when LL brought out viewer 3.4.1.  It's unlikely to be the same problem now, but it's similar.  The problem then was incompatibility with Microsoft's Sky Drive (or the Amazon equivalent Cloud Drive).  If nobody else here has a good idea, you may want to submit a JIRA report and perhaps refer to that old bug.

[Innula Zenovka]

I don't know if it can have much to do with the old bug. That only happened when SL was trying to open windows inside the viewer with Windows Explorer (because something about the changes Sky Drive made to Windows Explorer meant the viewer didn't like it). Since the OP's problem is happening with notecards, though, which aren't dependant on any external programmes, I don't thing the the two issues necessarily have much in common except they result in crashes when you try to open something.

[Rolig Loon]

Probably true, although the Sky Drive bug was triggered by a variety of file operations. I agree that this can't be the same bug, but it's doing sort of the same thing.