Can't type inches scale into measurements box

Good afternoon.

I use an iMac computer (late 2015 model 27") and cannot, when scaling an object, type a value in inches into the measurement box. Millimetres work fine but when I type the figure and the ‘inches’ (") symbol on my Mac keyboard, the value disappears and all I am left with is the inches symbol. I’ve been into the keyboard settings and in the ‘Text’ tab have unchecked the ‘Use smart quotes’ box as advised by John McClenahan but this has still not worked. Has anyone any idea as to why I am having this problem and, if so, how it can be fixed.

Many thanks.

Regards.

Andrew

Click and release on the desired scale handle to start scaling, move the cursor in the desired direction, click and release to drop the scale handle, and THEN type in the dimension with the double quote for Inches.
scale

Many thanks for your really prompt reply. We will try reproducing your solution this evening.

Kind regards.

Andrew