Join the AMA (Ask Me Anything) with the Firefox leadership team to celebrate Firefox 20th anniversary and discuss Firefox’s future on Mozilla Connect. Mark your calendar on Thursday, November 14, 18:00 - 20:00 UTC!

This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

Does Firefox ovewrite critical system files in windows OS?

more options

I work in a school district. We are using Tyler student information software. I have both Firefox and IE 10 on our computers. Tyler works but sometimes it won't update the student rosters. We were using IE then found that Firefox worked better. We still have random problems with Tyler. Our superiors contacted Tyler and they told us that it is not their problem but a Firefox problem. They said Firefox overwrites critical system files and that we now have to reimage all our computers. Is this true that Firefox can overwrite critical system files?

I work in a school district. We are using Tyler student information software. I have both Firefox and IE 10 on our computers. Tyler works but sometimes it won't update the student rosters. We were using IE then found that Firefox worked better. We still have random problems with Tyler. Our superiors contacted Tyler and they told us that it is not their problem but a Firefox problem. They said Firefox overwrites critical system files and that we now have to reimage all our computers. Is this true that Firefox can overwrite critical system files?

Valgt løsning

Thanks for the update; hopefully other Tyler users will find this in web searches and benefit from your research.

Les dette svaret i sammenhengen 👍 2

All Replies (4)

more options

Firefox shouldn't overwrite system files, critical or otherwise. Did support say what files Firefox overwrites?

Windows include a program to repair damaged system files which you can run to see whether that makes a difference: Use the System File Checker tool to repair missing or corrupted system files. I think that's worth running to test this theory.

Firefox will modify some registry settings to make itself the default browser if you approve that. If the Tyler software doesn't work when Firefox is the default browser, you can have IE make itself the default browser as a workaround.

more options

Is the Tyler software a browser-based application? In that case, here are some other troubleshooting suggestions:

When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Bypass Firefox's Cache

Use Ctrl+Shift+r to reload the page fresh from the server.

Alternately, you also can clear Firefox's cache completely using:

orange Firefox button (or Tools menu) > Options > Advanced

On the Network mini-tab > Cached Web Content : "Clear Now"

If you have a large hard drive, this might take a few minutes.

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either:

  • right-click and choose View Page Info > Security > "View Cookies"
  • Alt+t (open the classic Tools menu) > Page Info > Security > "View Cookies"

In the dialog that opens, you can remove the site's cookies individually.

Then try reloading the page. Does that help?


Many users have recently become more aware of privacy and either made changes to their cookie settings or installed extensions that stop some information from reaching websites. While this reduces tracking, it also can cause some site functions to break.

As a test, try using the application in Firefox's Safe Mode in a Private Browsing window. This will help bypass restrictive cookie settings, as well as other filtering behaviors of extensions, to see whether those are a factor.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled

In the small dialog that should appear, click "Start in Safe Mode" (not Reset)

Then open a private browsing window using either:

  • Ctrl+Shift+p
  • File menu > New Private Window
  • orange Firefox button > New Private Window

In that window, try Tyler. Any difference?

more options

Thank you for your replies. What was happening was the experts at Tyler insisted our problem was Mozilla Firefox. They claimed Tyler would not work on IE if Firefox was installed. They suggested I reimage all computers without Firefox. That was not an option. Well what I found out was that IE 11 is being pushed out and is not compatible with Tyler so my teachers were getting this update unknown to them. IE 10 also has issues, but IE 8 and 9 work great with or without Firefox on the computer. Firefox is well like at our school.

more options

Valgt løsning

Thanks for the update; hopefully other Tyler users will find this in web searches and benefit from your research.