The restrictions on the scanner driver in the Mac OS X 10.11 El Capitan environment are shown below.

< The guide message is displayed when the scanner driver is launched. >

[Phenomenon]

When the scanner driver is launched, the above guide message may be displayed.

When you select Yes:

The TWAIN driver (ScanGear) is launched. Scanning using MP Navigator EX or IJ Scan Utility can be performed.

Here, the ICA driver cannot be launched. The product name is not displayed in Image Capture, therefore, you cannot perform scanning using Image Capture.

When you select No:

The TWAIN driver is not launched, therefore, you cannot perform scanning using MP Navigator EX, or IJ Scan Utility Ver.1.x.

[How to make ICA driver available]

Launch Image Capture, go to [ File ] -> [ Reset TWAIN devices ]. ICA driver can be launched, and you can perform scanning using Image Capture. If you perform scanning using MP Navigator EX or IJ Scan Utility after scanning using ICA driver, the above guide message is displayed again. Therefore, select Yes or No so as to launch the driver you want to use.