Solution for slow QuickBooks performance is several areas, including opening centers, opening blank invoices, opening the Find window, saving transactions, and others. Explains that slow performance can have sevearl causes, and that many of these have been fixed in the most recent update.

It is sometimes necessary to uninstall and reinstall all other Intuit programs in the QuickBooks installation folder (as well as QuickBooks),  if QuickBooks does not function correctly after a reinstallation. This is referred to as a clean install.

This article describes why a connection to the company file may have been lost and how to troubleshoot a resolution.

Lists the QuickBooks files that need to access the Internet through a firewall. Includes QuickBooks versions 2005 through 2009 and later.