updated 08:42 pm EDT, Thu July 26, 2012
Xgrid removed; AutoCad, Perian, DAVE non-functional in Mountain Lion
With any new OS revision, the community's general tendency is often "upgrade first, ask questions about compatibility later." The excitement of obtaining the latest OS and its new features sometimes interferes with normal "best practices." While Microsoft has recently announced both Office 2008 and 2011 are compatible with Mountain Lion with patches, a handful of high-profile applications are not yet compatible with Cupertino's latest OS, which may lead to headaches with productivity, or just everyday computing tasks for hasty upgraders.
According to report aggregator RoaringApps, popular games such as Assassin's Creed II, architectural leader Autocad Mac 2013, the Citrix ICA client, SMB/CIFS supporting software DAVE 9.0, the Iron Mountain secure backup utility v8.6 and QuickTime video codec package Perian fail to function on Mountain Lion, even though each worked in Lion. Apple does provide guidance in the event of a failed boot attempt after install, but it does require delving into some troubleshooting steps, rather than automatic elimination of any problem items.
In mission-critical installs, MacNN recommends that a full and bootable clone of the hard drive's existing system and software be created prior to any significant OS update. This usually allows for a full restore in the event of a failure of vital software following install. In addition, users should apply every available upgrade for installed software prior to the new OS installation. Mountain Lion does automatically attempt to "quarantine" incompatible applications or low-level kernel extensions that don't work properly, but in some instances misidentified software could prevent completion of the upgrade process, leaving a non-functional OS install in its wake.
In the case of a truly critical machine where failure or delay costs a significant amount of time or money, MacNN recommends waiting at least a week to allow late developers to get their updates out, or not upgrading at all in the short term. Software like the excised Xgrid will not be replaced by Apple, and other vendors of older software may not provide a compatibility upgrade at all.
The golden master (final version) of Mountain Lion was made available to developers only two weeks ago, which with some companies didn't allow for sufficient pre-release testing on the retail-complete version of Mountain Lion. Prior OS upgrades have a history of catching some developers and users off-guard in terms of unforeseen compatibility issues, but time -- along with a "rollback" clone backup -- generally mitigates the teething problems of the new OS quickly.