When you move or copy a worksheet from one Excel workbook to another workbook in Microsoft Office Excel 2007, unused styles are copied unexpectedly. In this case, the file size of the target workbook is larger than expected.
To resolve this issue, apply the following update:
2553026 Description of the Excel 2007 hotfix package (xlconv-x-none.msp, Graph-x-none.msp, Excel-x-none.msp): August 30, 2011
Registry key information
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in WindowsAfter you install the hotfix package, to have us enable the hotfix for you, go to the "Fix it for me" section. If you prefer to enable the hotfix yourself, go to the "Let me fix it myself" section.
Fix it for me
To enable the hotfix, click the Fix it button or link. Then click Run in the File Download dialog box, and follow the steps in the Fix it wizard.
For Windows 8
For Windows 7, Windows Vista, Windows XP, Windows Server 2008 or Windows Server 2003
Install hotfix that is described in Microsoft Knowledge Base (KB) article 2553026 before you run this Fix it solution.
This wizard may be in English only. However, the automatic fix also works for other language versions of Windows.
If you are not on the computer that has the problem, save the Fix it solution to a flash drive or a CD and then run it on the computer that has the problem.
After you install the hotfix package, follow these steps to enable the hotfix:
Click Start, click Run, type regedit in the Open box, and then click OK.
Locate and then select the following registry subkey:
On the Edit menu, point to New, and then click DWORD (32-bit) Value.
Type DisableCopyUnusedCustomStyles, and then press ENTER.
In the Details pane, right-click DisableCopyUnusedCustomStyles, and then click Modify.
In the Value data box, type 1, and then click OK.
Exit Registry Editor.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.