After all, I have 100 other network devices that think my network is just fine.

We found that the printers are very sensitive to broadcast traffic.

We solved the problem by putting the printers on a VLAN to separate them from the main network.

If your network is small look for a malfunctioning pc or server that is sending out a lot of broadcasts.

Try restarting DHCP, and possibly removing the reservations altogether in favor of setting the printers to static IPs.

We tested both successfully but used the print servers for our setup in the end.

We also tried all the basics - firmware, drivers, cabling, IP conflicts, etc.

The two Zebra GX420ds worked fine when connected directly to a laptop or on a small network with a switch and a laptop, so the hardware isnt failing.

The problem springs up on both of them at the same time when it does happen.

The problem did go away after I rebooted servers, however, which includes 2008 R2 and 2012.

The theory Ive seen that I think holds the most potential is these printers having sensitivities to something in the network environment - number of broadcasts, etc.

I could have dug into this more, used Wireshark, etc, but why These printers are not that expensive and my time is extremely valuable.

I would think that this information would be valuable to Zebra since it has happened to a few of us now, some having more affected Zebra printers than others.

But, they referred me to a reseller instead who then became stumped.

But dont worry Zebra, your reseller was happy to sell me a different brand, so Im all taken care of now.

But i have a physical Machine too where i cant revert to a Snapshot.

Zebra Zdesigner Gk420D Driver For Mac