No, you can't connect to Excel files hosted on local storage devices. This is because Geckoboard needs to periodically access your spreadsheet in order to push any changes to dashboard widgets powered by it.
You'll need to host your file on an always-on web server. The easiest way to do this is by using a cloud storage service. Geckoboard supports Dropbox, Google Drive, One Drive for Business as well as any other cloud service able to provide a direct link to files.
We have dedicated articles for connecting your Excel spreadsheet to Geckoboard using the following cloud storage providers:
If you're using a different provider, see our article on Connect your Excel spreadsheet using cloud storage.
If you have any further questions about hosting your Excel spreadsheet, please drop us a line.