Export to MS Excel format is not available

In Crystal Reports 8.5 and later, the option to export to Microsoft Excel format is not available in the 'Format' box of the 'Export' dialog box. Previously, the option was available. Why does this behavior occur and how can the export to Microsoft Excel format be made available?

There are three possible reasons why the option to export to Excel is no longer available.
• A virus update was recently installed
• The Excel export DLL was moved, renamed or deleted
• A third party application was installed

NOTE: The name of the file that handles the exporting to Excel depends on the version of Crystal Reports in use.
• CR 8.5 may use both u2fxls.dll and crxf_xls.dll depending on the different Monthly Hot Fixes, Weekly Hot Fixes and/or Service Packs that have been applied. If you are using u2fxls.dll, it is located in the C:\WINNT\CRYSTAL folder. If you are using crxf_xls.dl, it is located in the C:\Program Files\Common Files\Crystal folder.
• CR 9 and 10 use crxf_xls.dll

To correct this behavior perform the following steps.
1. Quit Crystal Reports.
2. In Control Panel, double-click 'Add/Remove Programs'.
3. Select 'Crystal Reports' and then click 'Change'.
4. In the 'Crystal Reports Setup' dialog box, click 'Reinstall'.

If after performing the steps above, the Excel option is still unavailable in the 'Format' box then perform the following steps.
1. Quit Crystal Reports.
2. In Control Panel, double-click 'Add/Remove Programs'.
3. Select 'Crystal Reports' and then click 'Change'.
4. In the 'Crystal Reports Setup' dialog box, click 'Add/Remove'.
5. Expand 'Export Support' and then click the arrow next to 'Excel Format'.
6. Click 'Entire feature will be installed on local hard drive', then click 'Next' and then click 'Next' again.
7. Once the installation completes, click 'Finish'.
8. Open Crystal Reports and then export the report.