There is a FileOpen plugin for MAC users so you should be able to open SEDs on your MAC. However, there are sometimes problems and especially for laptop users.
When you open a document from the British Library, check next to the Apple logo on the top left hand corner of your screen to check the program being used to open the document. If you can see 'Preview' then you are using the MAC default program which is NOT supported by the FileOpen plug-in. You need to install Adobe Reader (if you do not have it already) by visiting www.adobe.com Then install the plugin from plugin.fileopen.com/all.aspx (select the MAC version). You then need to open Adobe Reader which should prompt you to set it as the default reader. Click 'yes'.
Go to fileopen.bl.uk and click on the link that says 'Click to download a FileOpen test document' - this will display the FileOpen Delivery Page.
Your document should open automatically in a few seconds. If it does not, then click the link underneath to download it manually.
If your browser applies security settings you may need to use 'Download File' from the options on the pop up bar at the top of the screen.
Once you allow the download, click on 'Open'. The file should display on the screen saying you have successfully opened the test document.
You should now be able to open FileOpen documents from the British Library.