Today I was playing around with Gmail’s offline mode and testing out Thunderbird 3 to see which I preferred for offline mail access when I temporarily disabled the offline mode. Once I decided on Gmail’s offline mode for mail access, I tried to re-enable it and was greeted with this message: “Failed to load required resources Failed to enable local store”. This means that enabling offline mode failed and I wouldn’t be able to use it for accessing my mail. After some Googling I found that this was a very common problem and often occurs when disabling and enabling offline mode. I 
couldn’t find a real fix for the problem, but here is what I did to fix it on my computer.
1: Make sure offline mode is disabled for your Gmail account. To do this, open your Gmail account using the “Offline Mail” shortcut that was made when you first enabled the offline mode. Next for to settings, offline mode and click on disable.
2: Next remove Google Gears access to Gmail by clicking on the wrench button on the right of the Google Chrome interface and then select options. Click on the “Under the hood” tab and scroll down to the Web Content section. Click the “Change Gears Settings” button. Now click the blue remove button next to all of the Gmail addresses. Click Apply and close out the options menu and then exit Chrome.
3: Delete your Google Gears profile. It should be located in “C:\Users\(User Name)\AppData\Local\Google\Chrome\User Data\Default\Plugin Data”. If you can’t delete the Google Gears folder then open Taskmanager and make sure that all instances of Chrome have been closed. If you are still having problems then you may want to install Unlocker and use it to delete the folder. If you can’t find the Google Gears profile, then you may want to install the Everything Search Engine and then search for it.
4: After the Google Gears profile is delete, run Ccleaner with all of its options for Google Chrome checked. You can leave the “Saved Form Information” box unchecked.
5: Now open Chrome, log into Gmail and enable offline access.
Hopefully the above steps have helped you solve the “Failed to load required resources Failed to enable local store” error message in Gmail. If it didn’t but you found another way to fix this problem, then please let us know in the comments.