Hi 

I'm having a problem with a file in excel that is about 28 000 KB in size and it contains data, mainly pivot tables.

My issue is when trying to save either excel crashes or it says there were errors in the file and it needs to repair them. However it never does and saves it as a file not as an excel worksheet.

when I try to retrieve it from unsaved workbooks in my C drive, it contains so many errors, most of my formula are #N/A and all my pivot tables are gone.

I have lost a large amount of work because of this.

Can anyone help? 

Hi,
According to your description, I think the issue may be caused by some reason.

1) Excel workbook disk cache full
When you save an existing file in Excel, Excel creates a temporary file in the destination folder that you specify in the Save As dialog box. The temporary file contains the whole contents of your workbook. If Excel successfully saves the temporary file, the temporary file is renamed with the file name you specify in the Save As dialog box.

Workaround:
1. Excel creates a randomly named temporary file (for example, Cedd4100 with no file name extension) in the destination folder that you specified in the Save As dialog box. The whole workbook is written to the temporary file.
2. If changes are being saved to an existing file, Excel deletes the original file.
3. Excel renames the temporary file. Excel gives the temporary file the file name that you specified (such as Book1.xls) in the Save As dialog box.

For more detail information, please refer to the following link:
http://support.microsoft.com/kb/814068/en-us
The article applies to Excel 2003, but we can refer to it.

2) Repair the file and set Save AutoRecover

Manually repair step:
1. On the File menu, click Open.
2. In the Open dialog box, select the file you want to open, and click the arrow next to the Open button.
3.             Click Open and Repair, and then choose which method you want to use to recover your workbook.
For more detail information, please refer to the following link:
http://office.microsoft.com/en-us/excel-help/repairing-corrupted-files-in-excel-HA001034656.aspx

The article applies to Excel 2003, but we can refer to it.

Configure the AutoRecover settings, follow these steps:
1. Under Save Workbooks, click to select the Save AutoRecover info every check box to turn on the AutoRecover feature.
2. In the minutes box, you can type any integer from 1 through 120. This box sets the number of minutes that will occur between saves.

The default is 10 minutes.
3. In the AutoRecover file location box, you can type the path and the folder name of the location in which you want the AutoRecover files to stay.

The default location is as follows:
drive:\Documents and Settings\user_name\Application Data\Microsoft\Excel
 
For more detail information, please refer to the following link:
http://support.microsoft.com/kb/289273/en-us
The article applies to Excel 2003, but we can refer to it.