I have had this exact problem with two N750s. I RMA'd the first one and when the second one exhibited the exact behavior, I requested help at the support portal on 10/26 [Deleted - Trancer] and never heard back. Today I opened another case [Deleted - Trancer] with the hopes of getting someone’s attention.
Problem:
The N750 causes a hard lock with either of my xboxes in under 5 minutes. It is a hard freeze and the xboxes can only be physically turned off with the button at this point. The freezing occurs whether playing a game like Borderlands 2, watching streaming movies via Netflix, etc or connecting to a Windows 7 computer running Windows Media Center. I do not play in the multiplayer mode. I use the online xbox cloud storage for saving my games. If I disconnect the xbox from the internet (unplug the ethernet cable) before I start it, there is no problem with freezing.
The problem started as soon as I installed the N750. It goes away if I go back to *ANY* of my older routers (DIR-655, WRT-54gl, USR5461, DIR-601) and returns the moment I reinstall the N750. If I use any other wireless router changing NOTHING else, there are NO problems. PROBLEM ONLY OCCURS WHEN THE N750 IS BEING USED.
In my case, I have narrowed the issue down to some sort of problem between my HDHomerun Prime tuner from Silicon Dust and the N750 that causes either or both xboxes to completely lock up. I can play on the xbox for hours but as soon as I turn on the HDHR, the xbox 360 locks within a few minutes. I contacted silicon dust and they said they have seen this problem before with a WD router but couldn’t tell me with which model.
Environment:
I have internet service via comcast cable.
The locking occurs whether I use the comcast tm502g modem or the tg862g modem. Currently I am using the tg862g modem which is set to router use only. The tg862g wifi feature has been turned off by Comcast.
Connected directly to the N750 via Ethernet are 2 computers plus an 8 port trendnet switch with 7 devices directly connected via ethernet. I also replaced the trendnet switch with an ASUS 8 port switch and have the same problems. One of the devices connected to the switch is an HDHomeRun Prime Cable TV tuner. Several of the computers are running Win7, one is running Win8, one is running OS X Lion. There are many wireless devices including ipods and one ipad.
I have one original xbox and one 4GB xbox. Both are directly connected to network via Ethernet. Both show the same symptoms of locking within 5 minutes.
Here’s what I have done to troubleshoot:
I have been using the WRT54GL wireless router with zero problems while I waited for my replacement N750 to arrive. When the replacement N750 arrived, I replaced the WRT54GL with the N750 and rebooted everything (TG862G, switch, HDHomerun, etc.)
Test 1
I did NOT run the WD setup. Just replaced WRT54GL with N750 and rebooted everything.
Results: Computers all able to access internet, xbox starts normally and signs into xbox live, but locks within 5 min. It never locks at same spot. Sometimes it locks at startup. Sometimes I can actually play a few minutes before it locks.
Test 2
Run WD setup, change password, setup wireless on both bands, etc. Firmware is v1.01.04 but I leave it.
Reboot everything
Results are the same. Xbox locks within 5 min.
Test 3
Reset N750 to defaults. Update firmware to lastest 1.4.16. Run N750 setup, set password, etc.
Results are the same. Xbox locks within 5 min.
Test 4
Connect xbox wirelessly over 5ghz with a Belkin wireless adapter.
Results are the same. Xbox locks within 5 min.
Test 5
Turn off Network UPnP on N750.
Results are the same with the xbox locking.
Test 6
Put WRT54GL back as main wireless router. Take out N750 completely.
Result. Everything works fine.
Test 7
Since all I really want is access to the 5 GHz band option, I also tried just using the N750 as an access point behind my DIR-601 and had the same issues with xbox locking.
Conclusion:
There is definitely a problem with the N750.
PLEASE read everything I’ve written carefully. Please DON’T tell me to reboot, reset, check firmware, or any other answer from your script because I’ve already done all of that. Please don’t blame the HDHomerun Prime. It works just fine with any other router.
Please DO offer help.