On the Remote Processing panel, if certain criteria are met (see list below), a warning message will be produced. The mouse cursor icon will then change and remain indefinitely as an hourglass. Interaction with the panel is still possible, however.
The criteria are:
1. No Geoprocessing Server is defined.
2. The 'Process jobs on remote geoprocessing server' option is checked.
3. When criteria 1 and 2 are met, the Apply button is pressed.
This is a known issue.
Click Apply a second time.