Allowing sessionStorage

ProtonMail uses the latest web technologies to secure your data, including sessionStorage. In this article, we will explain what sessionStorage is and address common issues. 

What is sessionStorage?

sessionStorage is a new web technology that allows you to store website information securely on your device. We use sessionStorage to store your mailbox password, which is used to decrypt all messages in your account. 

Without sessionStorage, we would need to ask you for your mailbox password every single time you read or send an email. 

I got an error saying I don’t have sessionStorage. How do I get it?

As the first step, check if your browser supports sessionStorage. You can find a list of supported browsers here.

For All Browsers: 

Please ensure that cookies are enabled.


1. Enter about:config in the address bar.

2. Click Accept the Risk and Continue.

3. Type in in the search bar. Change the value from false to true.


You can enable sessionStorage in Chrome and other Chromium-based browsers by following this article


Instead of using incognito mode, switch to regular browsing mode instead. sessionStorage is automatically enabled in Safari by default. 

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  1. Ron French

    I can not figure out how to create different storage boxes for each person that I correspond to and need to keep the email for future use. I know Im not being clear but it would normally go under the inbox icon.
    Thank you,

  2. Asma

    I am trying to log into my protonmail inbox but it is not letting me. It keeps taking me to a page that says “click here if you have a problem.” I clicked and I got here to comments. I need to login because I gave this email address to a potential employer whom I am in the middle of an exchange with and this is a crucial time for me to interact.

  3. Steve R

    I am using firefox 40.0.2 and it is loading a blank screen, will protonmail support this version as it was the only option when I recently installed firefox.

  4. KS

    The instructions for enabling sessions and allowing cookies appear to be incorrect (don’t follow the format of Chrome ver 65) and in conflict (ie cant both allow cookies and enable sessions). I may be misunderstanding the instructions, however.

  5. Fix Err Spdy Protocol Error

    There are many more issues while using the Chrome browser. One of the general issues is the error of Err Spdy Protocol. It appears when you are trying to open a new webpage. Last day when I was using the chrome this error appears again and again. Then I visit Fix Err Spdy Protocol Error for the help. I follow all the steps mentioned and now there is no such issue on my system.

  6. Anuki

    Hi, it seems i have maxed out by storage with just 62 emails… This cannot be right?

  7. Anuki

    it’s okay… problem solved! ;)

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