Much like Firefox allows you to install extensions, Greasemonkey allows you to install user scripts. If you are having a problem with Greasemonkey, first it is important to check if the problem is actually with the user script, just like a problem with Firefox may actually be caused by an extension.
These troubleshooting steps may help you fix the problem yourself, and if not they will help you provide information that will be required before anyone else can help you. If you can't solve your own issues, then please read about getting help from the community.
Add-on Enabled Status
Check whether the Greasemonkey extension is disabled, by Firefox.
- Go to Tools, Add-ons and check the add-on status.
- If the entry is greyed out, the Greasemonkey add-on is disabled.
- Click on the Enable button to enable the add-on. (Firefox must be restarted for this change to take effect.)
Greasemonkey Enabled Status
Greasemonkey itself can be disabled (independently from the overall add-on status). As long as it is disabled none of its scripts are run.
- Open the monkey menu.
- If the first item is not checked and does not say "Greasemonkey is active" then Greasemonkey is disabled.
- Click it to re-enable Greasemonkey.
Script Enabled Status
If you have installed a user script and it doesn't seem to work, or it used to work and does no longer, there are a few things to consider.
- Scripts do not run on every page. Check the monkey menu in the status bar. If it is not listed in the "User scripts for this tab" section, it does not run on this page.
- If it also does not show up in the "Other user scripts" section, it is not installed at all.
- The script must be enabled in order to function. Is the script's name greyed out? When you select does the first item say enabled with a check mark? If not, click this line and try again.
Script Install Errors
If user scripts are shown as plain text when you attempt to install them, Greasemonkey might be disabled.
- See Greasemonkey Enabled Status for more information.
- Make sure the script file's extension is .user.js.
All scripts running in Firefox (even Firefox itself!) will log errors to the Error Console. Reading the Error Console can thus be tricky, as it can contain a lot of unrelated information. Nevertheless, it can be an invaluable diagnostic tool.
If your problem is of the "when I do this, I expect that, but that doesn't happen" variety, the Error Console may contain some information indicating why.
- Click Tools, Error Console
- Click Clear so that old errors do not get in the way.
- Click Errors so that only errors (and not just warnings) are displayed.
Now load the page, and click the button or link or whatever other action you attempt that doesn't work. Do new lines show up in the error console? They may contain the clue needed to figure out what is wrong, and why. Right click on each and choose Copy, so that you can paste the information into an email.
Firefox stores all of a user's preferences and settings in a profile. This includes browsing history, cookies, saved passwords, installed extensions, all settings, and other personalized data. You can read more about profiles at Mozilla's support site.
Unfortunately, sometimes the Firefox profile can become corrupted, causing all kinds of problems. Also, it's possible for two Firefox extensions to break each other, which is difficult to recognize.
Thankfully, there is a straightforward way to find out if either of these have happened. You can create a second fresh profile, run a test in it, and then remove it and switch back to your existing profile with nothing lost.
You can follow Mozilla's "Managing Profiles" instructions, with screenshots and videos. For clarity, the steps are also explained here
First: Start the profile manager.
- For Windows, click Start, Run... and type: firefox -profilemanager, then click OK.
- For Linux and Mac, just type firefox -profilemanager at the console.
Then: Select Create Profile..., click Next, and in the box that comes up type a name, like "test". Click Finish. Select the profile you just created, and select Start Firefox.
After the testing step below is complete, repeat step two, but select the original (probably "default") profile, rather than creating a new one, to switch back.
The point of creating a fresh profile is for it to be fresh and clean. Unfortunately, plenty of software injects itself into Firefox globally, and can continue to cause problems even in a fresh profile. Once you've created and started your fresh profile, open Tools, Add-Ons, and check if any extensions are listed. If so, disable all of them and restart Firefox before continuing.
With this fresh profile running, you should see Firefox at its completely default settings, like after the first time you ran it.
First: Install Greasemonkey and restart Firefox. Open Tools, Error Console. Is anything displayed there? It should be empty. If not, right-click and copy the text of each, these details can be important.
Second: Install user scripts, preferably one at a time, and check after each that everything is working. If adding one causes a problem, please note which script it was.
Third: If you've installed all your scripts, and everything works OK, another extension may be conflicting. Install all the other extensions you have in your normal profile, one by one, and note which if any causes the problem to return.
Details of exactly what you noticed, and when, while running through the steps above are invaluable for anyone else to help you. Take them with you as you try getting help.