I have three computers set up. One is the host with the company file for quickbooks and the other two are users that connect to the host to work with the same file. They all work fine but off and on the two user computers wil give an error saying that... "cannot communicate with company file" then it talks about firewall issues. I have configured the firewall on all computers to aloow all the programs that Quickbooks help stated. Sometimes they all work for a week then it stops for a few days. Anyone have an idea as to how to fix this. The only other thing I can think of is to uninstall all quickbooks and start over. But I would like to avoid that if at all possible. Thanks

The next time it happens, try powering the router off/on.

Do you have a multi user package of Quickbooks? Check to see if Quickbooks allows the behavior you are using. If not, disable the live update feature in Quickbooks. It may be disabling the networking.