Are you allowing any history to be saved? In Preferences > Privacy, is the checkbox for "Remember my browsing and download history" checked? I do not think the back button will work if that is not checked.

@finitarry, Thank you very much for taking the effort fot replying. I did all the possible things I could do, including your advise. But I discovered that there was something wrong in my ~/Library/Mozilla/Firefox/Profiles/ ~/Library/Application Support/Firefox/Profiles/

Even renewing had no sense. So I reinstalled the Firefox completely. In that respect the problem is "solved"!

I was too quick in using "solved". In the newly instaled Firefox I keep having this problem, in spite of your advise....

There is one more thing you could try. No guarantee it will work, though. If you type about:config into the address bar, then agree to the promise that you will be careful, you can change this setting:

browser.cache.check_doc_frequency - set to 2 (meaning never)

If the page is in the cache, there should be no problem in retrieving it, provided that the page itself is not being prevented from caching.

finitry! Thank you again. I'm not a great hero....If this action fails, becomes a disaster, the end of everything (I'm a pesimist), can I than reset this action? Further: do I have first to open a certai site? F.i. a site as I have dscribed in my topic? So, when I click on an url on a certain site, after arriving there, not being able to return to the original site? Thank you in advance! Gr.

You can also open the links in a new tab with a middle click on the link.
That way you do not need to use the Back button, but can simply close a tab or otherwise return to the previous tab.
Also make sure that you have the cache enabled and that the cache is working.
Check the current cache usage on the about:cache page.

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Both @finitarry and @cor-el, I thank you very very much for your exceptional quick, relevant an helpful advises. For the time being I'm very glad with the advise " open the links in a new tab with a middle click on the link". That works perfect.The other advises I will test later as well, and I am very confident that they will work as well. As far as I see it, I regard my problem as solved and as "very helpful. Thank you both again very very much. I wish you all the best!

I'm sorry to come back (I don't blame you). I have to tell you that all the actions as described above did not work, or I could not find the cause. Only one advise, "open the links in a new tab with a middle click on the link", is very useful. I'm considering now to reinstall the Firefox. For that action I saved already all my bookmarks.

Strange....I found the solution finally elsewhere: Preferences/Tabs deselect "New windows in new tab" (free tranlation)