Categories: Computer email program (please specify: Apple Mail, Outlook, Thunderbird, etc) :

Importing from Outlook PST to Gmail - Unknown Sender

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Importing from Outlook PST to Gmail - Unknown Sender Aquitaine 6/25/09 5:35 AM

There are a couple other posts about this but they end with explanations or solutions that aren't applicable in this case. Here's the problem:

I am migrating all of my personal email from Outlook to Gmail. My Outlook mailbox is about 1.4 gigs and is currently connected to an Exchange Server (2007), though only the last few years' worth of mail are actually Exchange; everything before that was POP.

The problem is that a huge number of my emails are showing up in Gmail as (unknown sender). I've read that this has to do with emails that come from a local address on your exchange server, though none of mine do (mine is the only account) -- and what's more, the emails that show up this way seem to be almost entirely from before I switched to Exchange. All the messages I've archived since switching to Exchange a few years back seem to be okay.

My first attempt was with the Google Email Uploader. I've tried setting up my Google Apps account via IMAP and trasferring them via drag-and-drop. I've set up a Mercury mail server on my local machine and transferred them via that  intermediary, using Vista's WinMail and then Google's mail fetcher to get them off of the Mercury server. It all turns out exactly the same way. I haven't tried using Thunderbird to do the actual IMAP transfers by hand yet as I've sunk the last 24 hours or so into this and figured it was time to ask for help before sinking more.

The only reference I was able to find to anyone solving this problem (outside of removing things like ClearContext, which I don't have) was to scrub various Microsoft email headers off of every single email. I don't know how to do this or which headers I'd be looking for. Any suggestions?

Thanks so much,
Re: Importing from Outlook PST to Gmail - Unknown Sender no spam from usenet 6/25/09 7:45 AM
I am having the same  problem, I posted a question here several days ago and no-one has answered, here is the original thread:-

If you read it I think we have both looked at the same answers.
Re: Importing from Outlook PST to Gmail - Unknown Sender mathieu.chateau 6/30/09 7:45 AM

I have the same issue. My understanding is that the Google webmail read sender from smtp header of mails. Mail sent through exchange from internal to internal doesn't have smtp header, as it stayed inside the orgs. Mail sent from someone outside the orgs have their name displayed.

Mail client (outlook and Thunderbird) display correctly senders, finding the info the mail body i guess.

I tried uploading through the google email uploader, from outlook moving mail from one account to the other, and thunderbird. Same issue all the time (source mails don't have smtp sender/receipt).
Re: Importing from Outlook PST to Gmail - Unknown Sender Aquitaine 6/30/09 10:07 AM
I've never received email from anyone via an internal Exchange server, though. All of the (Unknown Sender) emails are regular old emails. It's over 3,000 of them (out of about 7000 total) and the older I go, the more likely they are to show up that way, but it's as you say - even after moving them to Gmail, a regular IMAP client (Outlook or Thunderbird or WinMail) will correctly read the headers. Gmail won't.
Re: Importing from Outlook PST to Gmail - Unknown Sender 7/14/09 1:45 PM
I also have this issue, and would like a solution.  However I do have a large number of internal emails, that I need to retain To and From label information, even if the email link is invalid.
Re: Importing from Outlook PST to Gmail - Unknown Sender Bryan.Brookessmith 7/24/09 7:28 AM
I have the same problem and have around 15GB of e-mails I'm archiving, but I am slightly relieved by the fact that IMAP client display them correctly, as this means the data is all still there, if only GMail would display it correctly too.

Maybe we just all need to pester the GMail developers to get this looked at?
Re: Importing from Outlook PST to Gmail - Unknown Sender Aquitaine 7/24/09 8:57 AM
I've been trading emails with Google Enterprise Support about this for the last month or so, as a client of mine had the same problem.

From an analysis of several emails that showed up as (Unknown Sender) in the Gmail interface but correctly in the IMAP client, it appears that the problem is in the email headers 'From' and 'Sender.' Google wants all of the necessary information to be in the 'From 'header, while it appears that some emails just put a name in 'From' and put the address in 'Sender.' This does not just affect internal MS Exchange recipients. In my experience, it affected a lot of old emails (say, from 1997 to 2004) and the only time an Exchange server was even in the picture was from about 2005 to 2009 -- and even then, there were only a handful of internal addresses.

The Google tech I worked with verified the problem and indicated that the best solution right now is Goolge Apps Sync, which is only available to Premier/Education Google Apps customers. He said that he'd also filed a request with the Gmail UI team to maike better use of the 'Sender' field, but that he couldn't promise that they would do it. I sent them several examples and we walked through all sorts of processes for transferring the email to Gmail (drag-and-drop from Outlook, Mail fetcher, transfering to an intermediary Mercury Win32 server, etc).

At any rate, Google is aware of the problem, so now it just remains to be seen what they'll do about it.
Re: Importing from Outlook PST to Gmail - Unknown Sender hues 7/25/09 6:20 AM
Thank you, Aquitaine, for doing all this. It would be of great help if a solution comes up soon :)
Re: Importing from Outlook PST to Gmail - Unknown Sender redleman100 7/31/09 6:11 AM
I am testing Google Apps Sync for Oulook.
My sync is coming from an Exchange Server.
I do have the problem with the Gmail side having (unknown sender).
So the Google sync method has the same problem.
Re: Importing from Outlook PST to Gmail - Unknown Sender tucsondap 8/2/09 8:54 AM
I'm having the same problem - hundreds of emails IMAP'd from Outlook show as "unknown sender".   GOOGLE???
Re: Importing from Outlook PST to Gmail - Unknown Sender dircery 8/28/09 11:42 PM
I found a partial solution. I tried copying first via my home outlook 2003 which is not connected to the exchange server. This produced the same results as above. I tried it again this time from my work outlook 2007 which is on the exchange server. This time when I copied the mail to the imap server outlook found the internet address of all exchange users and substituted them in for the names.  Note: this doesn't work if the people in the e-mail are not presently on the exchange server (if they have been laid off for instance or if the text of the name doesn't exactly match the current name).

This solution seems to have fixed most of the e-mail problems. Hopefully google will fix it so that it at least displays the name in the from /to headers even if you can't actually send them mail.

Good luck.
Re: Importing from Outlook PST to Gmail - Unknown Sender WestLABoy 10/3/09 3:24 PM
To add to the discussion...

I had some success using Outlook's IMAP capabilities to copy over emails. It almost seemed as if the emails I initially downloaded using Outlook needed to be copied using Outlook, but those I initially downloaded using other clients (Apple Mail, Thunderbird) were fine no matter what.

I've never used Exchange, so that couldn't be the issue, I don't think.
Re: Importing from Outlook PST to Gmail - Unknown Sender davidlists 2/2/10 9:58 AM
has anyone found a workaround for this yet?

i'm having the same problem....emails created in outlook when i was formerly on an exchange server and were sent/received with other former users of that exchange server all show up as (unknown sender) in gmail.

this thread started 8 months ago and there are others going back almost a year

still no solution...?
Re: Importing from Outlook PST to Gmail - Unknown Sender davidlists 2/2/10 11:04 AM
update: please go to this link and click "star" at the bottom to register your vote on increasing the importance of this fix.
Re: Importing from Outlook PST to Gmail - Unknown Sender sailcomp 3/4/10 4:41 AM
same problem, no solution, google zZzZ?
Re: Importing from Outlook PST to Gmail - Unknown Sender Hideki Coder 4/11/10 12:08 PM
i've posted a new solution in the issue 40 url
anyway, i'll soon (2/3 days) delete that comment and add a new, better and polite one :D
with final instuctions.
Re: Importing from Outlook PST to Gmail - Unknown Sender 7/2/10 11:10 PM
This whole issue completely sucks to say the least.
I want to use gmail as my only email account, yet there seems to be no way to transfer email from one of the most popular email clients to date (Outook).  I have tried direct IMAP transfer from Outlook only to find out you are limited to 2 GB max due to IMAP only supporting the 97-2002 pst format, not the new 2003 version.  I have tried importing my PST files in Thunderbird then using an IMAP interface to gmail as well, however with Thunderbird I have unknown sender and corrupted email errors for every email I upload, even though Thunderbird shows send and receive and contents with no errors.  When I upload the limited amount of files direct from Outlook I get unknown sender on 30% of me emails, but I am unfortunately limited to only being able to upload a total of 2GB instead of the 5GB I have.
I can't understand why Google wouldn't put a Lab addon, or produce a free app so that people could upload the 2 types of pst file formats directly to Gmail with no errors, ugggh. 
This oversight and lack of solution interest from Google actually concerns me with respect to other Google products like Android phone etc.
Come on Google, dedicate a couple software developers for a couple weeks and solve this issue and you will be a hero and gain the potential of gaining more market share over Outlook users.
Re: Importing from Outlook PST to Gmail - Unknown Sender Ralf Haring 11/7/10 11:56 AM
I am trying to import emails from a PST and am experiencing this problem as well. It seems that all the email addresses of the people internal to the organization are not recorded in the message headers while those from outside are fine. I have not tried google apps sync as I am not a premier customer.

The only workaround I have found is to manually edit the headers, a very laborious process. Since it might help others with smaller amounts of files to import, here is what I did:
1) add PST to Outlook (2010 has a 60-day trial version) and configure gmail imap connection
2) drag email to gmail
3) configure thunderbird to connect to gmail imap
4) drag message to a local thunderbird folder
5) install the HeaderTools extension ( via
6) edit thunderbird's local copy of the message headers so they read ["First Last" ] instead of ["First Last"]
7) delete and expunge the message in gmail (if done from outlook or thunderbird, you have to delete it from each label it's associated with as well as the trash ... easier just to do it from gmail)
8) drag message from thunderbird to gmail and see the To/From/CC/BCC info displayed correctly
Re: Importing from Outlook PST to Gmail - Unknown Sender AK2K 11/10/10 1:13 AM
Hi Ralf, I am thinking of going through your approach, wanted to just check re step 6:

a) how long did it take you - is it possible to do this for ~20k messages?

b) this looks like a typo, no? "so they read ["First Last" ] instead of ["First Last"]"

Best from Dubai,
Re: Importing from Outlook PST to Gmail - Unknown Sender Ralf Haring 11/12/10 12:07 PM
Yes, looks like the comments strip out angle brackets. What I entered manually in the header is ["First Last" ^^] with angle brackets (greater than and less than signs) instead of carets around the email address. Hope this formatting works this time

I didn't do this operation for all the message in my PST as it would be a *ton* of work. I just did it with a few to verify that the workflow was possible. Ideally there could be a Thunderbird plugin which could analyze the messages in a local folder, strip out any To/From/CC/BCC/Sender entries that didn't have email addresses, prompt the user to enter them somehow, and then modify all the message headers appropriately.
Re: Importing from Outlook PST to Gmail - Unknown Sender Ralf Haring 1/10/11 6:12 PM
I had been working on a tool to read the messages in a gmail account and create a spreadsheet with all the bad to/from/cc/etc headers for the user to update. However I just recently tried a pst->gmail conversion tool someone has written . Having previously copied the emails from the PST to gmail via Outlook and experiencing the "unknown sender" problem, I didn't think to try it before. Surprisingly it started importing the emails with the headers intact! It spat out errors quite frequently so it is not entirely bug free, but I will probably try to contribute to that project going forward. Since it may work with no problems for other folks, I thought I'd mention it here.
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