There is no question about that Microsoft is dedicated to making Outlook the personal information manager of choice for the future. In the process of introducing Outlook to the market, however, many users became quickly aware that Outlook was not an actual feature-for-feature replacement for two Microsoft products; namely, Schedule+, wherein users share/update their calendars over a network, and Outlook Express, which is still the only Microsoft product capable of subscribing to and managing subscriptions to news groups.
In the case of news readers, Microsoft simply refers to Outlook Express as the "Outlook Newsreader", which one may launch from within Outlook a number of different ways. Outlook can be used to handle both internet and inter-office email simultaneously, but Outlook Express must be invoked to subscribe to and read from an nntp, or news server.
In the case of calendaring, Outlook is not capable of sharing contacts or performing group scheduling tasks over a network without Microsoft Exchange Server installed to support it (which is a sizable investment to many, and not without headaches of its own). But Schedule+ has long been able to perform group scheduling functions without any special support server, even over a simple peer-to-peer network. Thus, Schedule+ support files are installed with Outlook during installation, provided Schedule+ is already installed and running on the system. Then, by selecting the option "Use Microsoft Schedule+ as my primary calendar", a button is then provided, which will allow a user to launch Schedule+ from within Outlook. In this way group scheduling capability is retained without the need for investing in a separate system, running Windows NT, and Microsoft Exchange Server.
Outlook 97/98/2000 - Use Microsoft Schedule+ as my primary calendar
If, from within Outlook (97, 98 or 2000), you have checked the option "Use Microsoft Schedule+ as my primary calendar", the [Launch Schedule+]-button will launch version 7.0 by default. If, however, you have version 7.5 installed and running at the time you push the [Launch]-button, it will bring that particular window to the forefront, and from then on the [Launch]-button will call up the 7.5 version.
In MS KB-article Q182105 you can read what MS has to say about this option.
This entire feature (ie. Schedule+ as primary calendar) was removed in Outlook XP (Q293651). Although coexistance between Schedule+ and Outlook XP still is possible, you're advised to move to Outlook entirely, as described in Q309261.
Should you have to import much data from your Schedule-file, than Outlook can appear to hang (stop responding). Follow the instructions in Q278086 to have Outlook show a progress-bar during import-actions, so you can see what it's doing.
I can't select "Use Microsoft Schedule+ as my primary calendar"; it's greyed out, or dimmed.
Outlook searches for Schedule+ 7.0 files on your system before it will offer the option to use Schedule+ as your primary calendar. If 7.5 is the only version installed on your system, the option will remain greyed out. You must find and install version 7.0 before Outlook will allow you to check this option. The easiest place to find version 7.0 is on the Office95 installation CD.
But, ... there is a work-around. As described in this white paper from MS, you can enter a new key in the Windows Registry: UseSchedPlus.
Stop Outlook through the menu [Exit and log of]. Make a backup of your registry-files. Start the Registry Editor and browse to HKLM\Software\Microsoft\Office\8.0\Outlook\SchedPlusOption. At that point you make a new 'Reg DWord' with the name 'UseSchedPlus'. Change the 'Value' from '0' (which is the default) to '1'. When you now start Outlook, it will tell you that Schedule+ is configured as the program to manage your agenda.
Remark: I've tested it with Outlook98 and Windows95 (OSR2) and it works: Outlook gives the aforementioned message and starts looking for Schedule+. However, with a default setup of Outlook98, no version of Schedule+ is installed on the PC. So make sure to install Schedule+ before.
Remark: The option to 'use Schedule+ for group-scheduling' is made at the computer-level, not the user-level. For example, if multiple users work on the same computer, the Outlook-option to use Schedule+ for group-scheduling applies to all users working on that computer.
Can't I just edit the registry to put the Schedule+ icon on my Outlook toolbar?
Yes, you can. This MS Knowledge Base article (Q163144) describes how.
Error message: SCHDPL32 Caused an Invalid Page Fault in AWFXCG32.DLL
This problem can occur if you use Schedule+ in combination with Internet Explorer v.4 or v.5.
As Microsoft puts it: "Because this error occurs during the shutdown phase, there is no effect on your data". However, you may still want to get rid of this returning error-message. As this problem often occurs after installing Outlook98 or -2000 (which install IE4 and IE5, resp.), the solutions are described in a KB-article about Outlook: OL97: Outlook Caused an Invalid Page Fault in AWFXCG32.DLL [Q175314].
In the above text you can find a short description of the (im)possibilities of the interoperability of Schedule+ (v.7.x) and Outlook (various versions).
Should you, however, want to learn more about the intricacies of co-operating these programs in one network (or even on one computer), then the following articles may be of interest.