Microsoft last week confirmed that customers running Office for Mac will experience problems with the suite on Apple's new Lion operating system.
The most serious of the bugs crashes Communicator when Office for Mac 2011 users try to send an instant message or start an audio or video call.
Communicator is the corporate version of Microsoft's consumer-grade Messenger chat client -- it's available only to volume licensing customers -- and is also the software Mac users run to connect to Microsoft's enterprise communications server software, Lync 2010.
"We will fix this issue in an upcoming update to Communicator for Mac," said Pat Fox, senior director of product development with Microsoft's Mac group, in a company blog Friday.
Fox did not specify a timetable for the Communicator fix, but said later in the blog that users can expect updates "in the near future."
A second major bug may not affect most users either.
"On Lion, Outlook can't import mail from Apple Mail," Fox acknowledged. "We're reviewing this and don't yet have a plan to fix it."
According to a Microsoft support document, neither Outlook, which is included with Office for Mac 2011, or Entourage, the email client bundled with Office for Mac 2008, will reliably import messages from Mail.
This bug impacts users who install Office only after upgrading to Lion: Those who had earlier imported messages from Mail to Outlook or Entourage on, say, a Mac powered by Snow Leopard, won't be affected.
Outlook is not included with the lowest-priced Office for Mac edition, Home & Student.
Other Lion issues range from crashes in certain situations while running Excel or PowerPoint to a date format glitch in Word, said Microsoft in its support document.
Also, MSQuery, the tool that business users run to pull data into Excel from their corporate database, works only in English on Office for Mac 2011, and not at all in Office for Mac 2008.
And Office for Mac 2004 won't run on Lion at all.
That suite, released over a year-and-a-half before Apple switched to Intel, was written solely for PowerPC Macs. But with Lion, Apple has dropped support for Rosetta, the emulator that allowed programs compiled for the PowerPC to run on Intel processor-equipped Macs.
Although Office for Mac 2004 doesn't work on Lion, Microsoft will not retire the aged application suite until early next year: It has promised to support Office 2004 with security updates until January 10, 2012.
Like many third-party programs, Office for Mac 2011 and Office for Mac 2008 also lack support for many of the Lion-specific features that Apple introduced with Mac OS X 10.7, such as Auto Save and Versions.
Fox said nothing about when, or even if, Microsoft would add support for those features and others to Office for Mac.
Microsoft did, however, try to head off critics who may wonder why the company wasn't able to address Office's issues by the time Apple shipped Lion. In the support document, the company said it had been working with Apple "from the early days of Mac OS 10.7," and claimed "many issues were addressed leading up to the Lion release."
Office for Mac 2011 comes in two retail editions -- Home & Student and Home & Business -- priced at $149.99 and $279.99, respectively, and is available from Microsoft directly or through sellers like Amazon.com.
Microsoft does not sell Office through Apple's Mac App Store.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, or subscribe to Gregg's RSS feed . His e-mail address is firstname.lastname@example.org.