Many websites/add-ons store data related to your use of the website/add-on. Some use only cookies, while others ask Firefox to store larger data. The folders under [profile]\storage\default are where those large chunks of data are stored.

I think you recognize mail.google.com but the other one is not familiar to me. It seems related to a search add-on.

Firefox Storage

You can manually review and remove cookies and storage data from sites using a feature on the Options page. To find that:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the left column, click Privacy & Security and then in the right side, scroll down to the Site Data section. The "Settings" button opens a box listing all sites storing data and you can remove the ones you don't recognize.

Note: There is a "Save Changes" button at the bottom right of the popup; if you can't see that, try reducing zoom (hold down Ctrl and tap the - key a couple times) to see whether that helps. Otherwise, you won't be able to complete the deletions.

Sketchy Add-ons

Here's my suggested procedure for tracking down and cleaning up bad add-ons and other hijackers. I know it seems long, but it's really not that bad.

(1) Open the Windows Control Panel, Uninstall a Program.

After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help in smoking out undisclosed bundle items that snuck in with some software you agreed to install. Be suspicious of everything you do not recognize/remember, as malware often uses important or innocent sounding names to discourage you from removing it.

Take out as much trash as possible here. If you're not sure, feel free to post program names or a screenshot of the list.

(2) Open Firefox's Add-ons page using either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons
• in the Windows "Run" dialog, type or paste
  firefox.exe "about:addons"

In the left column, click Extensions. Then, if in doubt, disable (or Remove, if possible) unrecognized and unwanted extensions. All extensions are optional; the troublemaker might not be obvious from its name.

Before Firefox 57, a link sometimes would appear above at least one disabled extension to restart Firefox to make the change effective. You can complete your work on the tab and click one of the links as the last step. In Firefox 57, disabling should be immediate, but you may need to reload pages to notice any change.

Any improvement?

(3) You can search for remaining issues with the scanning/cleaning tools listed in this support article: Troubleshoot Firefox issues caused by malware. These on-demand scanners are free and take considerable time to run. If they finish quickly and especially if they require payment, you may have a serious infection. I suggest the specialized forums listed in the article in that case.

Hopefully that will flush anything on your system and in your Firefox that could be a problem.

thanks for the reply. all your suggestion doesn't solve the problem. next time i use Firefox that particular entry doesn't show up. i am using firefox 59.0.2 (64bit).

these others i recognized and accepted: the one in question was deleted by malwarebytes but it will come back again:

about+newtab http+++download.cnet.com http+++www.tomshardware.com https+++askbobrankin.com https+++googleads.g.doubleclick.net https+++ir.ebaystatic.com https+++mail.google.com https+++signin.ebay.com https+++support.microsoft.com https+++tomshardware.onesignal.com https+++tomshardware.os.tc https+++tpc.googlesyndication.com https+++www.cnet.com https+++www.extraspace.com https+++www.microsoft.com https+++www.pcworld.com https+++www.techrepublic.com https+++www.techspot.com https+++www.tomshardware.com https+++www.yahoo.com https+++www.youtube.com

P.S. These kind of "links" shows website i visit sometimes. and this is the one Malwarebytes saus is a PUP. http+++jaleco.ysearchtab.com

See if these links help; https://www.bing.com/search?q=remove+jaleco.ysearchtab.com&qs=n&form=QBRE&sp=-1&pq=remove+jaleco.ysearchtab.com&sc=0-28&sk=&cvid=E84E07C81F2F4185B904F292E6FF6617

thank you again. While Malware is still e.g like a full version it will remove this folder for me so i a am not worry.

I don't understand why the latest version of firefox creates this folder.

anyway after malwarebyts becomes just "free", i have created a batch file that will remove this folder.

thanks case close for me.

Firefox shouldn't create a website storage folder unless you visit the website. Try blocking cookies for the site to see whether that helps: If a site does not have permission to set cookies, Firefox also does not allow it to store data that would end up under [profile]\storage\default.

Here's where you can set that up:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the left column, click Privacy & Security and then in the right side, in the History section, change the selector to

Firefox will: Use custom settings for history

To the right of "Accept cookies from websites" click the "Exceptions" button. Then paste

http://jaleco.ysearchtab.com

and click the Block button. Repeat with

https://jaleco.ysearchtab.com

Then finally click the "Save Changes" button.

Let us know how it works out.

See also:

• https://www.google.com/search?sa=N&num=100&q=ysearchtab+remove

thank to everyone that responded with suggestions/fixes. i think i will ok now.

This will considered as fixed and closed.