(CNN) -- A leap-year related glitch caused thousands of Zune MP3 players to simultaneously stop working late Tuesday and early Wednesday, Microsoft said on the product's Web site.
Microsoft issued the first Zune portable music player in 2006 to compete with the iPod.
The problem should resolve itself after 7 a.m. ET Thursday, Matt Akers of the Zune Product Team wrote on Zune.net. "A bug in the internal clock driver related to the way the device handles a leap year" is to blame, he said.
The issue was limited to older Zune 30GB models, the Web site said.
The Zune support page says users should allow the internal battery to fully drain. Then, after noon GMT on January 1, 2009 (7 a.m. ET), users should recharge by connecting the Zune to a computer or AC power.
Internet message boards were flooded with complaints about Zunes freezing, prompting Y2K-like speculation about end-of-year hardware or software problems.
"It seems that every Zune on the planet has just frozen up and will not work," posted a Mountain Home, Idaho, user on CNN's iReport.com. "I have 3 and they all in the same night stopped working."
Another iReporter said he was working the night shift at a Toys R Us store in Puerto Rico when his Zune player and the Zunes of four co-workers all failed about 1:30 a.m. ET Wednesday. iReport.com: They all froze up
"It froze and there was no way to turn it off so you just have to wait until the batteries went dead. You can't push any buttons or anything," Carlos Colon told CNN. Colon said he owns a first-generation 30GB model. Watch Colon describe how his Zune suddenly froze up »
Other users reported their Zunes rebooted but froze when the startup status bar reached 100 percent. A post on Zune.net titled "Help-frozen zune!!!!" had attracted more than 19,000 comments by Wednesday afternoon.
Some Zune users dubbed the crisis "Y2K9" or "Z2K9," a reference to New Year's Eve and concerns over potential widespread computer failures on January 1, 2000 -- fears that proved unfounded.
Microsoft posted this statement Wednesday morning on the Zune Web site: "Customers with 30GB Zune devices may experience issues when booting their Zune hardware. We're aware of the problem and are working to correct it. Sorry for the inconvenience, and thanks for your patience!" The company said it would keep users posted via the support page on http://www.zune.net/en-US/ (zune.net/support)."
Microsoft released its first Zune 30GB music player, a competitor to Apple's popular iPod, in 2006. No widespread glitches have been reported this week in its second-generation 80GB or 120GB models.
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