Change a date with ExifToolGUI

[spruce18b]

I need help in changing a date with ExifToolGui.

I have installed ExifToolGUI into the same directory as Exiftool.exe.

In the Windows Explorer, the modified date and time shown for the first file in my pictures directory is 2014 Apr 13 18:11; for all other files the time is one minute later. These modified dates and times are correct, but

a) the dates and times, except for the year, actually refer to the dates and times that the pictures were taken, not modified.
b) the year must be changed from 2014 to 2012

In the Windows Explorer, the times and dates shown for creation refer to the point when the files were copied from a memory stick, not the times and dates when the pictures were taken. The dates span an interval of two days from Oct 15 to Oct 16, 2012.

In ExifTool GUI, in the left panel, the modified times and dates are shown as described above, i.e., two years too late.

I highlight a file name, and highlight a tag name FileModifiedDate 2014:04:13:18:11:50:04:00, click on the up arrow beneath EXIF and change the year from 2014 to 2012 and SAVE.

There is no change in the Windows Explorer or in the GUI left panel, even if I press F5 to refresh the screen. The year 2014 remains unchanged. This procedure also failed with the Def option.

Please explain what I am doing wrong and how to make it happen.

[MicroSSSG]

Similar issue, but I can only add filecreatedate to "custom" and not "workspace" and I can not change the date from custom...