Certain Firefox problems can be solved by performing a Clean reinstall. This means you remove Firefox program files and then reinstall Firefox. Please follow these steps:

Note: You might want to print these steps or view them in another browser.

1. Download the latest Desktop version of Firefox from http://www.mozilla.org and save the setup file to your computer.
2. After the download finishes, close all Firefox windows (click Exit from the Firefox or File menu).
3. Delete the Firefox installation folder, which is located in one of these locations, by default:
   • Windows:
     • C:\Program Files\Mozilla Firefox
     • C:\Program Files (x86)\Mozilla Firefox
   • Mac: Delete Firefox from the Applications folder.
   • Linux: If you installed Firefox with the distro-based package manager, you should use the same way to uninstall it - see Install Firefox on Linux. If you downloaded and installed the binary package from the Firefox download page, simply remove the folder firefox in your home directory.
4. Now, go ahead and reinstall Firefox:
   1. Double-click the downloaded installation file and go through the steps of the installation wizard.
   2. Once the wizard is finished, choose to directly open Firefox after clicking the Finish button.

Please report back to see if this helped you!

Code changes regarding HiDPI support for high resolution displays have landed in Firefox 22 and later (bug #844604).

You can modify the layout.css.devPixelsPerPx and increase or decrease the value in 0.1 or 0.05 steps to adjust the size of fonts and other elements in Firefox.

• The layout.css.devPixelsPerPx pref is a String value parsed to a float and allows to fine tune the dimensions of all elements (user interface and web pages) more precisely (resolution 0.1 or 0.05).

• Change the default value -1 to 1 to make it work like in previous Firefox versions (100%)

Start with a value of 1 and adjust this value with 0.1 steps or 0.05 for finer adjustments.

• Use values between 1.0 and about 0.5 to reduce elements in size (do NOT go all the way to 0.05!)
• Use values greater than 1.0 to magnify and make elements larger (percentage divided by DPI, % / DPI).
• http://kb.mozillazine.org/about:config

If web pages needs to be adjusted after changing this pref then you can look at the Default FullZoom Level or NoSquint extension.

• Default FullZoom Level: https://addons.mozilla.org/firefox/addon/default-fullzoom-level/
• NoSquint: https://addons.mozilla.org/firefox/addon/nosquint/

Use this extension to adjust the font size for the user interface:

• Theme Font & Size Changer: https://addons.mozilla.org/firefox/addon/theme-font-size-changer/

see

• https://support.mozilla.org/en-US/questions/959696
• https://support.mozilla.org/en-US/questions/963035
• https://support.mozilla.org/en-US/questions/963027
• https://support.mozilla.org/en-US/questions/963010
• https://support.mozilla.org/en-US/questions/962979
• https://support.mozilla.org/en-US/questions/962990
• https://support.mozilla.org/en-US/questions/963001

i have the same exact problem too any web page i open the resolution is huge. i have already uninstalled and re installed firefox but nothing works i am to the point of getting rid of firefox for good i have windows 7 and i have firefox

Hello chanelle.r, you don't have to getting rid firefox, try cor-el's reply :

You can modify the layout.css.devPixelsPerPx ........

the uninstalled and re-installed does not work with this issue.

thank you

Code changes regarding HiDPI support for high resolution displays have landed in Firefox 22 and later (bug #844604).

You can modify the layout.css.devPixelsPerPx and increase or decrease the value in 0.1 or 0.05 steps to adjust the size of fonts and other elements in Firefox.

• The layout.css.devPixelsPerPx pref is a String value parsed to a float and allows to fine tune the dimensions of all elements (user interface and web pages) more precisely (resolution 0.1 or 0.05).

• Change the default value -1 to 1 to make it work like in previous Firefox versions (100%)

Start with a value of 1 and adjust this value with 0.1 steps or 0.05 for finer adjustments.

• Use values between 1.0 and about 0.5 to reduce elements in size (do NOT go all the way to 0.05!)
• Use values greater than 1.0 to magnify and make elements larger (percentage divided by DPI, % / DPI).
• http://kb.mozillazine.org/about:config

If web pages needs to be adjusted after changing this pref then you can look at the Default FullZoom Level or NoSquint extension.

• Default FullZoom Level: https://addons.mozilla.org/firefox/addon/default-fullzoom-level/
• NoSquint: https://addons.mozilla.org/firefox/addon/nosquint/

Use this extension to adjust the font size for the user interface:

• Theme Font & Size Changer: https://addons.mozilla.org/firefox/addon/theme-font-size-changer/

hey Amalockh & chanelle.r.... don' t get rid with problem . you wll make your steps a/c to amitshree and if it will again make you rid try out steps a/c to cor-el ,it works surely. chaneller.r try reset firefox from" Troubleshooting Information" under help tab. For Theme Font & Size Change goto: https://addons.mozilla.org/firefox/addon/theme-font-size-changer/. it surely works............

Thanks for the replies everyone!

I have the resolution problem and just changed the layout.css.devPixelsPerPx to 0.05 as per your suggestion and now my browser is so super miniature that I can't see a thing. I then uninstalled firefox and reinstalled it and it remained the same size. I can't even see anything on the screen or the toolbar or anything it is so small. I obviously can't change the value back. I had to use chrome just to come on here. How do I change it back? I need to get on to firefox for work. It has all my bookmarks.

Hello msouthtash, when open firefox try to to zoom in, increasing the size, press and hold Ctrl while pressing + (make it 3 or 4 or 5 times if needed), can you access now in visible form the About:config ? if yes change the layout.css.devPixelsPerPx to 1 .

thank you