* Gives new details on controversial shareholder event

* Vendor Broadridge says no glitch in its technology

* Broadridge major seller of online-meeting software

By Ross Kerber

BOSTON, Nov 2 (Reuters) - Symantec Corp (SYMC.O) said technical problems led the security software company to overlook questions from shareholders at its controversial online-only annual meeting in September.

Several shareholders complained at the time their questions were not accepted or were softened by Symantec in what they said looked like an effort to shield executives.

Symantec has said it did not mean to quiet its critics and promised next year it will add back a "live" portion of the event.

In an Oct 27 letter, the company's Chairman John Thompson went further and blamed some overlooked questions on technical issues. Asked for more details, a Symantec spokeswoman referred questions to Broadridge Financial Solutions Inc (BR.N), the vendor providing the service that hosted the online event and that lately has made a major push in the area.

In response to questions, a Broadridge spokesman sent a statement that read, "There was no glitch in Broadridge's technology." The statement said further that "(I)f there had been a problem with our technology for Symantec's meeting, we'd have addressed it then."

Neither company would make executives available to be interviewed. Symantec is the largest company to date to scrap its live annual shareholder meeting. Instead, it had shareholders log in to a website to listen to a presentation by executives and to send in questions remotely.

The focus on the September 20 meeting comes as companies adopt more online communications with their shareholders, a shift some governance experts worry could shut off dissenting voices.

In his letter, Symantec's Thompson said that during the meeting the company was aware of just two questions asked by shareholders and only learned later that more had been asked.

"To our surprise, after the meeting ended, we discovered that there was a time lag that occurred that caused a delay in Symantec seeing additional questions submitted due to vendor network and technology reasons," Thompson wrote in his letter to the Shareholder Forum, a investor communications organization that followed the controversy.

Broadridge has hosted a number of online-only gatherings since last year, including its own annual meeting. The online format can save companies thousands of dollars in staging and travel costs for events that often draw just a handful of shareholders.

Still some governance experts and shareholder activists say the meetings serve a valuable role as the rare moment when executives must accept questions from shareholders. They have pressed for companies to hold "hybrid" events, as Symantec has said it plans to do.

In the letter Thompson mentioned the company may also provide a phone-in option to allow shareholders to ask questions verbally.

The technical problems at the Symantec meeting were not the first glitch involving Broadridge, which among other things counts votes in corporate elections. In 2008, a Broadridge counting error meant that a vote tally had to be revised in a contest at Yahoo Inc (YHOO.O).

Executives have said the snag was unique to Yahoo's complex election, and insignificant in the context of its overall operations. These including printing and mailing out more than 6 million paper documents a day like proxy voting cards and corporate annual reports.

(Reporting by Ross Kerber; Editing by Derek Caney)