Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac Options) key, and then starting Firefox. Is the problem still there?

Thanks so much: so far so good. cheers

OK tried again after restarting system: the only way to solve it is to hold down the SAFE start key each time (SHIFT , select link) ...What???

Has there been any updates to FF in the background the past few weeks?

Never had this problem before. Would you recommend I uninstall FF and reinstall the earlier version?

Thanks ahead of time.

An update came out a few days ago.

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It could be the work of one of your add-ons. Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; <Control>(Mac:<Command>)<Shift> A)

In the Add-ons Manager, on the left, select Extensions. Disable a few add-ons, then Restart Firefox.

Some added toolbar and anti-virus add-ons are known to cause Firefox issues. Disable All of them.

If the problem continues, disable some more (restarting FF). Continue until the problem is gone. After, you know what group is causing the issue. Re-enable the last group ONE AT A TIME (restarting FF) until the problem returns.

Once you think you found the problem, disable that and re-enable all the others, then restart again. Let us know who the suspect is detective.

Txs. did as suggested: worked. It was AD Block plus (I had two version running at once.) Brilliant.

You should remove both, then install the current.

That was very good work. Well Done.

Thanks did as suggested: removed both and installed one at a time. YouTube block works fine.

End result: Cannot run ADBlock on my system without it opening the selected link and the Home Page (coming up on top) simutaneoulsy.

Decided to continue running AdBlock dispite this as the trade-off would be having to put up with a million and one ads. Lesser of two evils. Will try setting a new home page (using BING...yes, I know, windows prog. on a Mac! ) txs. again for the support.

Go here, and ask for help. Forum; Adblock Plus Homepage {web link}