First check the document by opening in another computer.
In case there was a corruption of the file because you were working on the same file.
There is a tip and habit I use and recommend for users.
When saving a file, suppose “my proposal”.
I would save it as my_proposal_27_feb_2013-1
and the file would become my_proposal_27_feb_2013-1.odp
Then after a few minutes of work, due to habit I would save it as
my_proposal_27_feb_2013-2 Only one character (the number) has to be changed when doing save as.
This is done even with auto save on at 5 minutes.
The advantage of this habit from the old days of computing and bad power supplies is that it reduces the chances of data loss.
If something bad happens, I lose at max a few minutes of work. Also I have old versions available in case I get stuck with formatting like a horizontal line which is not deletable.
This is a habit cultivated for all softwares on all systems. There is no issue of space and also (I just remembered) the big reason is that if the date is wrong the backup systems and archiving systems shall not destroy the latest versions.
Sometimes after many years if there is time, the old versions are selected and deleted.
Yes, people shall complain, but you still need to have a look at the 3TB harddisks available these days and compare to the size of your critical docs (puny).
Regards,
Khawar Nehal
http://dubai-computer-services.com