How To Fix HTTP Error 304: Not Modified

Some error messages are more straightforward than others. Some of them can actually be quite baffling, like HTTP error 304 – Not Modified.

If you ever encounter this error when trying to access a website, it must be hard to know what to do to either accessing whichever website you were trying to access and to fix the error.

In this article, we will cover everything you need to know about this particular error. Our goal is by the end of this tutorial you will not only be able how to fix it but also you should be able to understand this error in a certain amount of depth.

 

Is HTTP Error 304 Really An Error?

In a way, we say that HTTP error 304 is not really an error. We know this can be a little bit confusion because it seems like a contradiction. So, let us explain what we mean by this.

What HTTP error code 304 means is that there is a problem with the URL (Uniform Resource Locator) you are trying to access. This problem could be one out of two possible ones: one of the possible problems is that the resource for the URL that you are trying to access has not changed since the last time you accessed it; the other possible problem could be that the URL that you are trying to access has not changed since the last time you cached it.

In order for the error code 304 to be returned it needs to be allowed by the web browser that you are using.

Very often we encounter this error code when using search engines such as Google or Bing. This is because search engines will index or cache websites. However, search engines are not the only websites that index websites, so you may also when using other web services.

So, why would these web resources return this 304 error code? Well, they use this error code to communicate that they information they have indexed or cached on a specific URL has now become out of date. And this is why it is trying to prevent you from accessing it.

If you would like to understand the HTTP Error 304 a bit better, you should look at the HTTP cycle. This cycle is what web clients, such as web browsers, go through when trying to communicate with a web server. We present this cycle to you as follows:

• The web client will obtain an IP address directly from the IP name of the specific site you are trying to access. This IP name is actually the URL but without what normally precedes it (http:// etc.). How an IP name (e.g. http:// [Name of website]) is converted into an IP address (i.e., without the http:// part) has to do with the DNS or domain name servers.
• Once the IP name has been converted into an IP address, the web client will open what is known as an IP socket connection to it.
• Then, the web client will use the IP socket it has just open in order to write an HTTP data stream and send it to the Web server.
• Next, the web client will receive the HTTP data stream back from the web service as a response to the HTTP data stream it had previously written and sent out. The HTTP data stream or header that is returned will contain information including the status codes that have been determined by the HTTP protocol.
• Finally, the web client will parse the HTTP data stream for different kinds of essential information including the status codes determined by the HTTP protocol.

The HTTP error 304 happens when the web client receives a status code that it recognizes as out of date or 304.

The reason why we said earlier in this tutorial that this error is not really an error should have become obvious by now. So let’s move on to how we could go about fixing it.

 

What Can be Causing the HTTP Error 304?

As it is often the case when it comes to errors of this kind, there could be many different causes for HTTP Error.

One of the main causes for this particular error is when your computer has become infected by a virus or malware that has either taken control or corrupted the Internet browser you use.

Another possible cause could be that some rogue program has corrupted files related to your Internet browser.

There is a third possible reason why this error could arise: if you have recently installed or uninstalled some Windows software. Although it should not normally happen, sometimes when we install or uninstall Windows software the registry can become corrupted.

If the error message HTTP 304 displays on your screen when you are trying to access a website, it means that your computer has become somehow infected following one of the three scenarios that we have just gone through.

How Can You Fix HTTP Error 304? 

The first thing to say about fixing this HTTP error is that it is extremely rare to see it in a web browser. If any of the issues that we went through in some detail in the previous section should arise, the web resource that you are using in order to access the URL in question should just display a cache of the website that you are trying to access. This, as we saw, would more often than not be a search engine.

Because the web service (i.e., search engine) would believe that the cache of the URL you are trying to access has not changed since the last time you accessed it, it will just present you that specific website from its cache.

If the error message displays, you should follow these simple steps carefully in order to fix it:

1. Grab your computer.
2. Click on the start button.
3. In the search box, type in the following: command.
4. Hold down the CTRL Shift keys simultaneously and hit the Enter key. This action will cause for a dialog box to display on the screen.
5. Once the dialog box displays, click on the yes options. This action will cause a new dialog box to display.
6. Type regedit in the dialog box.
7. Press enter. You will be presented with the registry editor.
8. Then, choose the specific key that relates to error 304 that you would like to back up.
9. Select export from the file menu. This action will cause the save in list to display.
10. Next, choose the folder where you wish to save the backup key you have just created.
11. Then, you will need to type a name (this could be anything you choose but we would suggest you include the word backup in the name) into the file name.
12. Next, you will need to choose the selected branch in the export range box.
13. Click on save. This action will save the backup with the following file extension (.reg).
14. Then you should perform a scan for malware and viruses.
15. Click on the start button.
16. In the search box, type in the following: command.
17. Hold down the CTRL Shift keys simultaneously and hit the Enter key. This action will cause for a dialog box to display on the screen.
18. Once the dialog box displays, click on the yes options. This action will cause a new dialog box to display.
19. Type cleanmgr on the dialog box.
20. Press enter. This action will prompt the disk clean up to begin calculating the amount of space that you may be able to reclaim.
21. Once the disk cleanup has finished calculating the space, a dialog box will display.
22. Check the boxes of those files that you would like to clear. Typically, temporary files take up most of the disk space.
23. Once you have checked the relevant boxes, click on the OK button.
24. Update your drivers.
25. Install all updates available. You should always make sure that your Windows updates are acted on as soon as possible. But this would be a great time to update your software if you have not done it in a while.

If these steps do not fix the error for you, there is an alternative set of steps you can take. You could use the Windows system restore to restore your software to an earlier date before the time when this error arose. The steps are the following:

1. Grab your computer.
2. Click on the start button.
3. Type system restore into the search box.
4. Click on the enter button. This action will cause for different options to display.
5. Choose system restore from among all the different options and click on it.
6. If you are prompted to enter your administrator password, enter it. Otherwise, follow the onscreen instructions, choosing the time where you would like your computer to restore to until your computer is restored.

Fixing the HTTP error 304 – Not Modified takes a few steps but it is something that can be done quite straightforward.

If you would like to send us your feedback on this article or share your tips fixing this error with our readers, please leave us a message in the comments section below.