Please give us the version of Finale you are using and the computer operating system you are using. There is little we can do but guess at the problem until you do.

You should also "Submit a request" via the link above for this kind of a problem.

I have had the same problem a few months ago concerning 2014.15. MakeMusic Customer Success suggested the following, which you might try:

1. Close any open programs, including Finale.
2. Create a folder on your Desktop and name it "Finale Temporary" (without quotes).
3. Reopen Finale 2014.5.
4. Click Finale 2014.5 > Preferences.
5. Select the Folders section from the left-hand side.
6. Click the check box next to the final directory in the list "Temp Files" to open the "Choose a Folder" dialog box.
7. In this dialog box, select "Desktop" from the left-hand column, select your newly create "Finale Temporary" folder and click OK.
8. Select the Save and Print section from the left-hand side.
9. Select the "Save Preferences When Quitting Finale" option.
10. Click Apply.
11. Click OK to close the Preferences window
12. Close and reopen Finale 2014.5.

But mine is finale version 25, so can I solve it in the same way?

Also, if I closed finale, my work will gone isn't it?

but anyway, thanks for your suggestion!

Can you use either "Save As..." or Export to XML to save a record of your file?

Closing the program risks losing any changes you made to the file since you opened the program and may knock out the latest saved version.

This has happend to me also in the last two days.  2 Scores I was just starting on so it was no big loss.  I am trying the suggestion by Erik.  I am using 2014.5.6359 on Windows 7,  64 bit with an i7-2600 CPU

I tried this on a Mac, so I do not know, if the same procedure can be used on Windows.
On a Mac, I think it can be used for v25 as well. I tried it on Finale 2010 and 2014.15, and it helped to some extent.

I would suggest, that you contact MakeMusic support for a professional answer.