Start Outlook in Offline Mode (without opening it first)

I can’t believe how hard this was to find! There are numerous articles, including official ones that claim to answer this question, but all pretty much say the same thing:

“Click this button”


But that of course means Outlook is already running. Maybe you don’t want that. For example, earlier today I needed to open a profile that was connected to a “corrupt” mailbox, but I didn’t want to risk the offline version of the data, in case it turned out being the only copy I had left. I won’t bother listing a bunch of other reasons we might want to launch Outlook with the connection to the server disabled. I’m sure you’ve got your own anyway, otherwise you wouldn’t be here.

For years I’ve just found other ways to solve whatever my problem was, but not today; today I was finally fed up with all the bad advice on how to go about this (e.g. outlook.exe /safe – does NOT start offline)!

Its pretty much a sure thing that this button toggled a registry value somewhere. It is Microsoft Office after all, and just about every configuration is in the registry. The trick is knowing what key. Outlook 2013 and later seem to love their unreadable hex/binary reg values, so looking at this with the regedit’s FIND feature isn’t going to help. I decided to turn to one of my favorite tools: ProcMon

If you haven’t heard about ProcMon, you should do yourself a favor and check it out. It lets you see what reg/file/network/process profiling & thread activity a given executable is responsible for. Actually, you should save a copy of all the SysInternal utilities in case they find themselves in the cross-hairs of Microsoft’s “cloud-first” software ray gun.

After opening ProcMon and filtering out a lot of noise, I found myself looking at every RegSetValue event Outlook.Exe was doing. I then toggled the “Work Offline” button a few times and saw this entry being flipped back and forth:


Therefore, it would prove that the values are as follows:

Work Online



Work Offline




The registry editor is a little odd for this type of value. Its called a binary value, but actually stored in hex, so set it just like the picture above, with only four sets of numbers on the right. If you do, Outlook will open with the “Work Offline” mode enabled.

For what it’s worth, I’ve tested this with Outlook 2016 on multiple computers and also found a mention on the TechNet forums (only able to find this after learning about “00030398”) suggesting it works all the way back to Outlook 2007, so it’s probably reliable, even though it looks like a pretty obscure string of numbers.



10 thoughts on “Start Outlook in Offline Mode (without opening it first)

    • You saved me so much time today! 😀
      Through the years I have on occasion wanted to start Outlook offline, troubleshooting situations that never left me the time to go for all this search you did.

      I am verifying that the registry change worked fine for me too; I can’t thank you enough.

      My issue to solve today was Google G-Suite sync would start way sooner than Outlook, locking the pst file, and not letting Outlook open “as usual”. I have been facing this issue on multiple computers during the past year, and not letting Outlook (and Google sync) try to sync, solved the issue.

      Thank you again.

    • It is there on my computer, and I’m running 1908. Be aware that if your profile is not named “outlook”, you need to replace that part to match your profile’s name.

  1. Perfect! Thanks for this!

    Here’s another example of why one would want to start Outlook offline:
    I’m setting up a replacement PC and want to confirm all my Outlook File -> Options are the same. I’ve already moved/loaded signatures, dictionary, custom forms, stationary, rules, etc. etc. but short of risky registry exports/imports I am not finding a safe way to copy options like when to mark a message as read. Since I’m on Office365 and already have my .ost file synced to the new computer there’s no reason to download any more email to the old PC.

  2. That was really helpful. I’d deleted a folder that had important mail in it, and I knew an OST on an RDP would have it. This allowed me to go in offline, move the contents into the inbox and then go online, effectively recovering the mail.

  3. On my machine (Win 10, Office 2016 corporate) this “offline” setting seems to work differently. It allows Outlook to remember its state on exit – whether offline or online. Which is even better for me…

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