Last year, TiVo users experienced glitches that auto-erased recorded content. The culprit was Macrovision DRM, and it's back and as bad as ever in TiVo Series 3 for HD. CNet documents brand new errors that prevented viewing and recording content. (Link via BoingBoing.)
Unfortunately, glitches like this are only part of Series 3 users' worries. Hollywood and cable providers have forced TiVo to remove TiVoToGo and implement a host of DRM restrictions in this device. If a program is marked as "copy never" or "copy once," your TiVo must obey -- it doesn't matter whether the copy limit was put there on purpose by the cable provider or was a technical error, as in CNet's case.