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Wikipedia saves bandwidth by instructing your Web browser to store many parts of the site in its local cache (normally on your hard drive), so that they are downloaded only once. This includes articles you've previously viewed, images previously displayed, style sheets, JavaScript, etc.
Sometimes this has the undesired—and highly confusing—result that a recent change appears to be ignored. There may be other abnormalities, such as changes to the site's interface or changed user preferences have no effect.
When you encounter odd behaviour, please try instructing your browser to bypass the cache so that the whole page is reloaded even if there is a cached copy. Normally, revisiting the cached page, or clicking "Refresh" or "Reload", will cause the browser to ask the Web site if there is a newer version available, downloading only if there is; the instructions below explain how to over-ride this behaviour.
Do this before reporting the problem. If the problem persists, see Wikipedia:Bug reports.
In unusual circumstances, it may be worth clearing the entire cache, or—at the extreme—disable browser caching entirely. Clearing the cache might help the browser perform better if it has cached many items which are not likely to be viewed soon. Disabling the cache is not a long term desirable solution because it downloads everything from a Web site every time, even if you've just looked at them and they haven't changed. However, disabling the cache is a useful experiment to determine if caching contributes to a problem.
Contents |
Instructions for various browsers
America Online
- To completely clear the cache (see note above):
- Click on the 'Settings' icon, then 'Internet [Web] Options'. Under 'Related Settings', click on 'Internet Explorer Settings' and follow the instructions for Internet Explorer.
Internet Explorer
- To reload a page and bypass the cache:
- either: Hold the Ctrl key, and press F5.
- or: Hold the Ctrl key, and click the Refresh button on the Start bar.
- To completely clear the cache (see note above):
- Internet Explorer 7
- Click “tools”, "Delete Browsing History", and then "delete all". Make sure to click on the checkbox also delete settings stored by add-ons. Then click OK.
- Old versions
- Click on 'Tools' and then 'Internet Options' and choose the 'General' tab. Then click on "Delete..." under "Browsing history". In the 'Temporary Internet files' section, click 'Delete Files...'. You will then get a dialogue box asking if you want to delete just the temporary files, or all offline content. Choose the latter and click 'OK'.
- Internet Explorer 7
- To change cache settings (only do this if you are reasonably confident of what you are doing):
- Selecting 'Tools' → 'Internet Options' → 'Temporary Internet files' → 'Settings...' allows you to make advanced configuration changes to the cache.
- There is an option labeled "Check for a new version of stored pages:" This does not bypass the cache, it merely determines how often the browser asks if there is a newer version available.
- Selecting 'Tools' → 'Internet Options' → 'Temporary Internet files' → 'Settings...' allows you to make advanced configuration changes to the cache.
Konqueror
- To reload a page and bypass the cache:
- either: Press F5.
- or: Click the Reload button on the toolbar.
- (Unlike other browsers, Konqueror seems to bypass its cache whenever you reload a page.)
- To completely clear the cache (see note above):
- From the 'Settings' menu, select 'Configure Konqueror'. Scroll down to select the icon labeled 'Cache', and click the button labeled 'Clear Cache'.
Mozilla family
This includes Firefox, Netscape Navigator (versions 6.x and 7.x) and SeaMonkey.
- To reload a page and bypass the cache:
- either: Press both Shift and Ctrl and then press R. (Alternatively, hold down the Ctrl key, and press F5.) On a Mac, use the Command key instead of Ctrl.
- or: Hold down the Shift key, and click the Reload button on the navigation toolbar.
- To completely clear the cache (see note above):
- From the 'Edit' or 'Tools' menu, choose 'Preferences' or 'Options'. Expand the 'Advanced' options and choose 'Cache' or 'Privacy'. Click the button called 'Clear Cache'.
- In newer versions of Mozilla Firefox, you can easily clear the cache, history and cookies: Hold down the Ctrl and Shift keys, and press Delete (or Del), then choose what you want to remove. Or from the 'Tools' menu, select 'Clear Private Data'.
- For older versions of Mozilla Firefox, go to 'Tools' → 'Options' and click on 'Privacy' (picture of a key) in the sidebar of the window that pops up. Click the 'Clear' button that is next to the word 'Cache'.
- To disable caching (only do this if you are reasonably confident in what you are doing):
- For Firefox
- Choose Tools | Options...
- Choose Advanced at the top
- Choose the Network tab
- Change the cache size to 0 (zero).
- For SeaMonkey
- Choose Edit | Preferences...
- Expand the Advanced item near the left bottom
- Choose Cache item
- Change the Size value to 0 (zero).
- For Firefox
Opera
- Reloading a page:
- Press the F5 key to reload from the web (and bypass the cache)
- Or hold down the Shift key, and click the Reload button on the navigation toolbar.
- Or Empty the cache completely (see below).
- Or Click edit this page, and save the page without making any modifications (this doesn't affect the page history).
- To completely clear the cache :
- From the 'Tools' menu, choose 'Preferences'. Expand the 'Advanced' options and choose 'History'. Click the button called 'Empty now'.
- Alternatively, you can easily clear the cache, history and cookies: From the 'Tools' menu, choose 'Delete private data'. Click 'Details', make sure that 'Delete entire cache' is selected, and then choose any other data you want to remove.
- To disable the cache permanently (only do this if you are reasonably confident of what you are doing):
- From the 'Tools' menu, choose 'Preferences'. Expand the 'Advanced' options and choose 'History'. Click on the dropdown for 'Disk Cache' and select Off.
Prodigy family
- (cannot be cleared)
Safari
- To reload a page and bypass the cache:
- for version 3 or newer:
- either: Hold down the Command key, and press R.
- or: Click the Reload toolbar button.
- (In Safari 3, "regular" reloads will always bypass the cache. [1])
- for version 2 or older:
- either: Hold down the Command and Shift keys, and press R.
- or: Hold down the Shift key and click the Reload toolbar button. (This may not work in all versions of Safari)
- To completely clear the cache (see note above):
- From the 'Safari' menu, choose 'Empty Cache...' or hold down the Option and Command keys and press E.
- To disable the cache permanently (this method only works on old versions of Safari 2 on OS X 10.4 and previous versions, and is not recommended as it may potentially (although rarely) cause system instability):
- Quit Safari by choosing 'Quit' from the 'Safari' menu, or by holding down the Command key and pressing Q.
- Open a Terminal window by double-clicking 'Terminal' within the 'Utilities' folder, which is within the 'Applications' folder.
- Type the following commands, which are case-sensitive, each followed by the Enter key:
- rm -rf ~/Library/Caches/Safari
- touch ~/Library/Caches/Safari
- Quit Terminal by choosing 'Quit' from the 'Terminal' menu, or by holding down the Command key and pressing Q.
- Relaunch Safari.
Flock
- To completely clear the cache (see note above):
- Go to the Tools menu and click on Options
- Go to Privacy and then, under Privacy, click on Cache
- Click on Clear Cache Now
- Flock v1.0.8 for Mac Instructions:
- Go to the Flock menu and click on Preferences
- Go to Privacy tab and then, under Private Data (bottom field), click on the Clear Now... button
- Select the Cache checkbox (only, or in combination with other desired options)
- Click the Clear Private Data Now button
Google Chrome
- To clear the cache:
- Go to the Tools menu (the wrench on the upper right of the browser) and click on Clear browsing data...
- Select the types of data you want to clear
- On the Clear data from this period: drop-down list, select one of the following:
-
-
- Everything to clear all the data you selected;
- Last day to clear the data only from the last day;
- Last week to clear the data only from the last week; or
- Last 4 weeks to clear the data only from the last 4 weeks.
-
Server cache
The Wikimedia servers cache a version of articles for visitors who are not logged in. For these users, preferences do not affect the layout so each webpage is always the same. They are recreated (converted from wikitext to HTML) only when the wikitext changes.
This causes a few undesirable side effects due to bugs (or design) of the software:
- References to variables which give the current date and time (18 November, 10:28 UTC) ({{CURRENTDAY}} {{CURRENTMONTHNAME}}, {{CURRENTTIME}}) are not updated if not logged in.
- The cache for redirected pages contains the rendered HTML-page of the target; this is not "invalidated" (recreated from the article text) when the target page is updated. That is, if Article A is a redirect to Article B, subsequent references to Article A displays the cached copy of Article B even if Article A or Article B is updated.
Forcing the server to re-render
Bypassing your own cache might not be enough if the updated content that is not being properly displayed is contained in a template or other transcluded page. You may need to purge the server cache of old versions of the page in order for the new material to be visible.
The server can be instructed to refresh its cache of a page's contents with the action=purge URL parameter. Add this to the end of the URL, or in place of the action=edit or action=history.
For example, to purge this page—which forces the latest version of wikimarkup to be rendered to HTML—use
For technical pages you think may need to be purged often, include {{purge}}. Don't put this on article space pages.
Disabling page caching
As a last resort, you can adjust your user preferences to disable page caching entirely, using
- Preferences→Misc settings→Disable page caching.
See Help:Preferences#Misc settings for more information about this option. Be forewarned: you will be using more bandwidth, make the servers work harder and get worse performance with this option set. Use it as a last resort.
