Hi could you give us a few more details: 
What type of file?
Did you already give the file a name?
Are you just saving the file or just quitting, or do you have a modified file and you are quitting?
In the latter case do you see the save-confirmation dialog?

Additional information provided by Curt:

file is basic gnumeric spreadsheet I have been using for several years with name after modifying data I either quit or save and quit file turns gray and sits for 30 seconds to a minute then program shuts down re-open program to check that changes have been made generally the changes are recorded but on one or two occasions the changes were not accepted yes I see the save-confirm dialog hit saves and appears to lock up.

Thank you.

Curt,

would you be able to run Gnumeric from a terminal window (open a terminal and execute 'gnumeric')? If you can do you see any waring messages in the terminal?

Response from Curt:

here is what I got:
Fontconfig warning: "/etc/fonts/conf.d/50-user.conf", line 9: reading configurations from ~/.fonts.conf is deprecated.

That would suggest that something is taking a very long time during
shutdown.

Any chance of getting a copy of the spreadsheet in question to see if that
happens to us?  (As attachment here if you don't care who sees it, as
private email if you want us to treat it as confidential.)

This is a save-as-gnumeric problem: "exit" takes little time, "save-as" takes
a long time.

+ Trace 232419

A workaround is to resize the sheet to something smaller:

1. Open sheet
2. Right-click on a sheet tab and select Resize
3. Shrink to 256 columns and 65536 rows.
[That'll take a few minutes for the same reason as the save]
4. Save.
[A few seconds]

After that you should no longer be meaningfully affected by this bug.

This problem has been fixed in our software repository. The fix will go into the next software release. Thank you for your bug report.