At NetTeks Technology Consultants Inc. in Boston, founder Ethan Simmons said the phones were "ringing off the hook" with problem reports, including some in automated communications systems. In a few instances, a company's network was an hour late in releasing calls to customer-support staff at the opening of business, leaving the "agents sitting around twiddling their thumbs," Simmons said.

Those and other problems may have been caused by companies' failure to administer patches properly or to do it at all. Indeed, a few consumer devices were an hour ahead Sunday rather than an hour behind, as if overcompensating.

A mishmash of patches in place and not in place likely caused some other oddities. For example, TiVo Inc. warned subscribers last week that their digital video recorders might display the wrong time for three weeks and that some scheduled recordings might need to be altered. At least some TiVos ended up showing the wrong time Saturday in advance of the switch, but became correct Sunday.

Ron O'Brien, an analyst for computer-security provider Sophos PLC, noticed Monday that his laptop calendar told him he had a conference call at 10:30 a.m., but his BlackBerry listed the same event at 9:30 a.m. He dialed in one hour too early and found himself alone on the call.

"There's going to be this code or etiquette issue the next few days," he said. "It's not going to be life-threatening, but it's going to be — 'nuisance' is almost too big a word — it's going to be inconvenient."