Hi tracy_collins4,

From what I understand you're having this pop-up interfering while browsing websites. Did MAC support suggest deleting cookies?

You could try installing an Add-on for Pop ups : Poper Blocker - Popup blocker for FireFox {link}

Any of these from a search : "pop up blocker" from the Firefox Add-ons support website.

You could also try blocking certain websites from storing site data.

To do this :

1. Click the menu icon in your web browser
2. Click Options
3. On the left hand side click Privacy & Security
4. Under Cookies and Site Data click Manage Permissions...
5. Search or manually click the website that you want to Allow or Block
6. Click Block and Save Changes

Or

Warning!

"Clearing all cookies and site data stored by Firefox may sign you out of websites and remove offline web content. Clearing cache data will not affect your logins."

You could try clearing your stored cookies, and site data by accessing Clear Data... under the Cookies and Site Data.

Reference: Clear cookies and site data in Firefox

See also: Troubleshoot Firefox issues caused by malware

Hope this helps.

We have seen more reports on Mac about an empty 'as'php' file. Maybe you have some security software or extension that strips of the GET data from the link (?xx=xx), causing the server to send an empty as.php text file that Firefox wants to save instead of showing the actual ad.

• /questions/1263352 Firefox wants me to open or save a php file. I can't delete request.
• /questions/1257317 what could be causing multiple "as.php" files to show up on my desktop?

I have blocked the website listed in the pop up, cleared all cookies, deleted downloads and removed and reinstalled Firefox twice. Nothing is working. I don't have this problem on my other computers and did not have it on this one for the first couple of months. I'm not a super computer techy so not sure what else to try. My computer is straight out of the box and no security software has been installed.

Hello tracy_collins4,

Would you please take a look at this thread and see if the
Chosen Solution there will work for you too :

https://support.mozilla.org/en-US/questions/1263352

In case that doesn't do the trick for you (installing an adblocker, not a pop-up blocker) :

Even though you mentioned clearing all cookies; just to make sure, you could go to Preferences => Privacy & Security => Cookies and Site Data => Manage Data, and see if you can find any "linksynergy" cookies there - the name of the cookie is : "rmuid".