Hi, do you use the NoScript extension?

An optional setting in the NoScript extension is causing all file:/// URLs to load blank in Firefox 53.

You can turn off "Allow local links" for Trusted sites here:

NoScript "S" button > Options > Advanced > Trusted mini-tab

See attached screenshot

Or:

(1) In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste nosc and pause while the list is filtered

(3) If the noscript.allowLocalLinks preference is bolded and "user set" to true, double-click it to restore the default value of false

In my test, the results are instant: when this is on/true, files do not load, as soon as I set it back to off/false, back to normal.

Could you test that?

I do use noscript and thanks for your help. Your solution worked. I'm beginning to think noscript is more of a painintheass than a good privacy setting.

In my opinion, NoScript is for people who are paranoid about security and want to know a little something about a page before allowing any scripts to run, and then to run scripts only from sources they trust. It requires a lot of training.

NoScript was not designed as a general purpose privacy tool. There are many tracking blockers and other extensions which are more focused in that area and easier to use.