Sometimes when you restart your Macintosh running System 7.5, you may receive a warning message that the system was previously improperly shut down.

Under System 7.5, there is an invisible file of size 0 bytes called "Shutdown Check" at the root level of the startup volume. The presence or absence of this file is an indicator on whether the warning message is issued.

The General Controls control panel uses the Notification Manager to issue the message about improper restart. The file called General Controls Prefs in the Preferences folder is where the current checkbox setting of whether to issue the notification is kept.

During a normal shutdown or restart the Shutdown Check file is deleted by the Finder. When the General Controls control panel initializes, it looks for the presence of the Shutdown Check file. If it is found, then a crash situation is assumed. The found Shutdown Check file is kept and made invisible, if it is not already. If the Shutdown Check file is not found during startup, a new one is created. The creation time and date of the Shutdown Check file is the approximate startup time of the last successful startup for the System Folder of the startup volume.

Developer guidelines evangelize that dialogs not be issued during an extension loading time. This is why you do not see the notification as the General Controls control panel loads. The approved method for issuing messages from extensions is the Notification Manager. General Controls posts the improper shutdown warning notification to be displayed as the Finder comes up.

The notification message could be misleading if you switch between multiple startup volumes.

For example, you set the startup volume to be another volume other than the current volume. Before restarting normally you crash, and the computer starts up from the newly selected startup volume. You then operate from this new startup volume for a number of days. Finally you choose the original volume to startup from in the Startup Disk control panel and restart. The old Shutdown Check file is now found by the General Controls control panel and the system realizes that it was not shutdown properly the last time.

Another similar example might be after a crash, if you start up from a floppy disk. Restarting from the floppy-based System Folder does not generate an improper shutdown notification, but when you return to starting from the hard drive the warning notification is issued.

You should interpret the warning notification based on whether the current volume being booted from had shutdown normally the last time it was active.

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