The main feature change was support for Microsoft's 64-bit operating system, however support for Banyan VINES was also dropped from this version of MDAC. There were several known issues: MDAC 2.7 continued causing connectivity problems on clustered servers running Microsoft SQL Server 6.5 or SQL Server 7.0, with no workaround provided by Microsoft. When creating or configuring ODBC data source names (DSNs) using the Microsoft SQL Server ODBC driver the network library protocol might unexpectedly switch to TCP/IP, even if the DSN was configured to use named pipes. This issue was found by "InfoWorld" reporter Randall C. Kennedy, who identified that the change was actually made in MDAC 2.6 but was never documented. It was discovered when testing client/server database workloads on a Windows XP computer; "InfoWorld" claims that although overall server CPU utilization rose by only 8 percent using TCP/IP, context switches per second dropped by more than 150 percent (which is of course impossible because you would then have a negative context switch rate - the drop is either 33% or 60% depending on which planet the author was on at the time of writing) for a 10-user workload. They were unimpressed that a fundamental functional change to the default behaviour of Net-Lib occurred without more than a passing mention in an unrelated document. Windows XP users also sometimes experienced problems connecting to SQL Server because SQL Server attempts to use certificates it finds on the local computer, however if there is more than one certificate available it did not know which one to use. When attempting to use Microsoft Analysis Services 2000 RTM, an error would sometimes appear when trying to browse cubes. Microsoft also discovered a problem in Windows 95, Windows 98, and Windows Me's setup program which prevented the MDAC installation program from rolling back when it encountered an installation error.