The Windows wait cursor, informally the Blue circle of death (known as the hourglass cursor until Windows Vista) is a throbber that indicates that an application is busy performing an operation.

The wait cursor can display on programs using the Windows API.

Windows Vista introduced a new, animated wait cursor.

The wait cursor is a shared resource in the system across applications and windows.

[2] In Microsoft Foundation Class Library (MFC) the wait cursor can be controlled by CWaitCursor.