The messagebar is a less intrusive alternative to the messagebox. Unlike the messageBOX, which pops up with a critical messages requiring immediate attention or an unhandled error.
In contrast this messageBAR will not interrupt processing.
The messagebar shows informational messages, errors, and messages from the macro.
Sometimes it's really important information like letting you know your password is about to expire.
Other times it's just fyi info.
You can clear the message, skip to the next message, or if you don't want it to be blocking your view you can press the hide button and it will shrink into a little box with an exclamation mark in the corner.
Once you clear all the messages the box will disappear entirely until another messagbar message comes across.
*Versions 1.89j and above: Certain messagebar messages will automatically clear after 15 minutes.