Q I have switched from an old MacBook Pro to a new iMac 27”, carrying over my user information with Migration Assistant. One of the external drives on which I store image files is a WD My Book Studio, and since migrating I have had problems accessing some of the images on that drive, seeing the message ‘You do not have permission to open the document “x”. Contact your computer or network administrator for assistance.’ How can I repair its permissions?

A Before changing permissions on that drive, visit the WD support site, download and install the latest support software for your model. WD drives which have non-standard features such as this model can be dependent on their drivers, and an old set could present this type of weird error.

If that does not fix it, select its top-level folders in the Finder, and bring up Get Info dialogs for them using that command in the File menu. In the Sharing & Permissions section, set the permissions to give you as the top (owner) name, with Read & Write privileges. Then click on the cogwheel icon below and select the Apply to Enclosed Items… command, to propagate the change throughout each folder.

Updated from the original, which was first published in MacUser volume 30 issue 12, 2014.