The default directory created in QuickBooks Desktop to store company files is located at:
Windows 10, 8.0, 8, 7 and Vista: C:\Users\Public\Public Documents\Intuit\QuickBooks\Company Files
Company files may be saved in any location the user has appropriate rights to, however, there is no way to change the original default directory in QuickBooks. QuickBooks will automatically open to the last used directory when opening new company files or restoring backup files.
To change the default location for new files in QuickBooks Desktop:
The next time you open the file in QuickBooks Desktop, the No Company Open screen will show the location where the file is saved.