I have an occasional crash on saving a LibreOffice spreadsheet file,
working with Knoppix 6.4.4. Such crashes are hard to anticipate for
a specific incident, but I believe I can now express some likely
necessary conditions.

Prior to the crash a copy-and-paste operation has been performed.
This operation involved downloading a text file representing an on-line
matrix. From the text file, LibreOffice accommodatingly
reconstructs this matrix in an interim spreadsheet, from which a
partial copy-and-paste is performed to transfer part of the matrix
to another collection of spreadsheets.

It seems to be the case that if I take the time to close the interim
spreadsheet, for which I have no other use, then saving the spreadsheet
collection goes smoothly with no problems. If I do not take the time
to close the interim spreadsheet, there is an occasional crash of the
video system. This crash can be reset with ctl-alt-backspace, but the
copy-and-paste operation must be redone after such a crash.

I think it likely that a lot of LibreOffice and OpenOffice reports of
'crash on save' may be similarly explained, possibly in the word-
processor as well as spread-sheet modes of operation. Interim copy-
and-paste products may need to be controlled in a better fashion so
as not to corrupt the basic functions of which they are a part.