Indeed :clap:Today's Featured Article from MacFixit
Late-Breakers
Problematic USB hubs can wreak havoc under Mac OS X 10.4.x
On numerous occasions we've covered issues stemming from the presence of defective USB hubs. In most cases, the issues are device specific -- iPods failing to attain a proper charge or synchronize properly with USB 2.0 hubs, for instance.
We've recently seen an increasing number of reports indicating that malfunctioning USB hubs can also cause other, seemingly unrelated issues, including problems launching applications or performing other routine tasks.
What appears to be happening in these cases are stalls or other errors in the queries that Mac OS X applications, or Mac OS X components send through the USB framework. When the problematic hub is encountered, stalls or complete freezes can occur.
In some cases, different releases of Mac OS X can harbor varied sensitivity to defective USB hubs, so that a user running Mac OS X 10.3.x with a seemingly functional USB hub will suddenly experience significant issues after upgrading to Mac OS X 10.4.x.
Take the case of MacFixIt reader Gerry Brown:
"My home network consists of two serious development machines. One is a Cube running the 7457 1.3 GHz G4 with 2 MB L3 cache, 1.5GB memory and a 120GB HD. The other is a Shuttle PC running a 2GHz Athelon with 1.5GB memory and 200GB hard drive. The systems are tied together with a Compucable A-B switch the controls a Mac keyboard, Microsoft Wheel Mouse and a 19 inch NEC flat panel. Life was good.
"That was until I installed Tiger. From that point on my Cube started acting very weird. After waking from sleep, the apps would not work correctly. It appeared as if the permissions were wrong on my home directory. When any app started, it appeared to be running from scratch without all my settings. I couldn't save data. Mail could not store any messages, etc. You can imagine my angst.
"I tried scorched earth. A clean install of Tiger from an erased hard drive. I tried a new machine. I bought a Mac Mini (returned it in 2 days when the same problem existed). I posted on boards. I created a new user account. Nothing worked.
"I bought a D-Link USB/Bluetooth device so I could sync my new cell phone. This seemed to make the problem worse. Now when the system woke up (triggered by a mouse press), the mouse would not work.
"I had focused on either Tiger or my highly modified Cube. No deductive reasoning worked.
"What I didn't think of was that the problem could be with one of the three powered USB hubs that I use. One was specifically for the single USB connection on the A-B switch. I bought a cheap off-brand powered USB hub for the devices. That was the problem. I replaced that with a new powered hub and everything is working.
"So when the experts say to get rid of all your peripherals except the essentials, when debugging problems; listen."
MacDoc
Indeed :clap:
Is this a widespread problem, for all of the millions of 'off-brand powered USB hub' users, or something rare and specific?
Don't know but it's a worthwhile heads up when things go wonky to consider the hub as a possibility.
When I'm troubleshooting, I always start with "Is the computer plugged in? Are the peripherals plugged in?" and if the answer is yes, "Are they switched on?" then disconnect all and restart from a cold reboot. After a while, no one should be surprised how often those in need of help, while otherwise intelligent, do not think to plug in a cable.
Good article...
Had similar bad experience with one of my USB hub with myolder G4 PowerMAc. One point, the Mac would refuse to shutdown and would instead cycled through "restart" continously. For a while I thought it was a faulty power-switch or something. Long and behold, it was my cheap D-Link USB hub! Once disconnected, the Mac was happy again...
Ever since then, I try to buy better-quality USB hubs.
Had similar bad experience with one of my USB hub with myolder G4 PowerMAc. One point, the Mac would refuse to shutdown and would instead cycled through "restart" continously. For a while I thought it was a faulty power-switch or something. Long and behold, it was my cheap D-Link USB hub! Once disconnected, the Mac was happy again...
Ever since then, I try to buy better-quality USB hubs.
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