Compacting Outlook 2010 OST results in old emails being re-sent

Status
Not open for further replies.

Thomas Inman

Member
Outlook version
Outlook 2016 32 bit
Email Account
Outlook.com (as MS Exchange)
Hello Diane and fellow readers,

I have a customer running outlook 2010, connected to an offsite company exchange server, and I am compacting the OST now. The customer's OST file is 45GB!! Hence compacting is still running as I write this, 18 hours later.

The customer reported to me this morning that she was told people are receiving old emails from her, and I have never heard of compacting an OST causing this to happen.

This customer's Outlook OST is the largest I have seen since Microsoft changed the size limit from 20GB to 50GB.

My questions are, can compacting actually trigger old emails to be re-sent? And, how long should I continue to wait for compacting to complete? Or should I cancel compacting?
 

Diane Poremsky

Senior Member
Outlook version
Outlook 2016 32 bit
Email Account
Office 365 Exchange
compacting the OST
When it is an ost, it's not really necessary to compact it - you can delete it and let outlook resync. If the mailbox is huge and the internet connection slow, you can check the mailbox size online before deciding which route to take...

and no, i have never seen this reset in old emails being sent. it also shouldn't trigger read receipts being sent back - unless you empty deleted items before compacting.

If they are actual messages being resent, i would 1) verify in OWA that sent messages aren't stuck in the outbox and 2) delete the ost.
 

Thomas Inman

Member
Outlook version
Outlook 2016 32 bit
Email Account
Outlook.com (as MS Exchange)
The user has a 50 down/10 up connection with Comca$t, however I opted to not delete the OST because it's 45GB, and figured that would take a few days to download again.

She is relatively close to the maximum size for an OST, which I believe is 50GB, so I am hoping that her OST will actually shrink in size. I don't think it has ever been compacted before, spanning at least 5 years. She isn't a huge fan of technology, especially when it comes to computers, so I am going the extra mile to help her any way possible.
 

Diane Poremsky

Senior Member
Outlook version
Outlook 2016 32 bit
Email Account
Office 365 Exchange
if it is not erroring for her, then it is 50 GB (2010 started out with a 20GB default, but it was increased in an update) - and you can raise it higher, although microsoft doesn't recommend going too much higher.

Compacting has the potential to reduce it 20%, so you may recover a lot of space. (Outlook is supposed to automatically compact when there is 20% white space - which is harder to hit when the file is huge.)

My ost is 10GB and i deleted it earlier today hoping to fix a problem with rules (it didn't). It took about 2 hours to download from office 365 on a 100mbit connection.
 

Thomas Inman

Member
Outlook version
Outlook 2016 32 bit
Email Account
Outlook.com (as MS Exchange)
Update: Compacting had not finished after waiting 24 hours, though the progress bar was still moving toward completion (about 80% done on a 45MB OST file). This user needed her machine back asap, so time was up waiting for compacting to completely finish.

What improved significantly was no more spinning wheel mouse pointer waiting on background operations in Outlook 2016. Navigation is quick once again. I did not have an chance to see the resulting file size after letting it compact for that long a time, but I consider this a successful repair based on the user's positive feedback alone.

Regarding the issue mentioned earlier about the user reporting feedback from colleagues that received 'old' emails from her during the compaction: this appears to be a result of duplicates stuck in the Outbox for who knows how long, that were suddenly able to be sent out. I don't think the issue happens as a result of compacting necessarily, but it was a side effect in this user's case. No such problem exists now, and only a few of her colleagues received duplicate old emails - not everyone in her contact list. So, I believe Compacting an OST file is not harmful, but be prepared for the length of time it takes to complete on an unusually large file.
 

Diane Poremsky

Senior Member
Outlook version
Outlook 2016 32 bit
Email Account
Office 365 Exchange
I consider this a successful repair based on the user's positive feedback alone
Absolutely. My guess is there was either a huge email she deleted (into the GB in size) or a ton of little ones that needed cleaned up. Can't really guess on the size based on how long it took for that reason - but i'm expecting it went down a lot - probably close to half, if not more.

It may have been faster to re-sync it - this is one reason why microsoft recommends deleting ost files....
this appears to be a result of duplicates stuck in the Outbox for who knows how long
This may have been a big reason why outlook was so sluggish but they should not have been stuck there to begin with.
 

Thomas Inman

Member
Outlook version
Outlook 2016 32 bit
Email Account
Outlook.com (as MS Exchange)
I think your guess on the reasons behind the dramatic speedup in Outlook after compacting the OST is correct.

On another customer system, I did this process differently, deleting the OST, and waiting for a full re-sync. His mailbox was not as large (over 20GB), but still took almost 24 hours to download everything. I watched the count as emails came in, and it was through short bursts with long pauses in between that the re-sync slowly finished. That was with an Office 365 Business plan/Exchange mailbox about 12 months ago.

I haven't figured out the rate O365 transfers data, or more specifically, the pattern, but from my own observations, it seems to be a start/wait/start process. This seems strange to me considering Microsoft has virtually unlimited bandwidth.
 
Status
Not open for further replies.
Similar threads
Thread starter Title Forum Replies Date
S Outlook 365 Can I change the possible range of highlighting colours when writing an Outlook email? Using Outlook 1
B Outlook 213 keeps crashing. I just found out there are DMP files. How can I tell Why? Using Outlook 2
H Outlook 2016 related mails in outlook Outlook VBA and Custom Forms 11
S Outlook 2021 Can you make emails from 3 word domains "safe" by entering top 2 word domain into Safe List in Outlook? Using Outlook 1
@ Outlook Using Outlook 2
kburrows Outlook 365 - Ribbon Customizations Disappear Using Outlook 0
D Wishlist How to use 'app password' in Outlook 2003 after Google pulled plug on "less secure apps" Using Outlook 1
L Restoring Outlook from backup pst file Using Outlook 5
e_a_g_l_e_p_i Kernel Outlook .pst viewer Using Outlook 3
L Outlook 365 Outlook not working on linux how to solve it Using Outlook.com accounts in Outlook 0
T Outlook 2019 Using Gmail aliases in Outlook Using Outlook 6
S Activities in Outlook Outlook VBA and Custom Forms 3
S ios outlook Using Outlook.com accounts in Outlook 0
W Transfer Outlook 2016 autocomplete file to Outlook 2007 Using Outlook 1
V iCloud calendar problems, Outlook shuts down immediately Using Outlook 2
S Outlook Macro for [Date][Subject] Using Outlook 1
E Outlook - Macro - send list of Tasks which are not finished Outlook VBA and Custom Forms 3
E Outlook - eliminate same adresses from to, and bc line Outlook VBA and Custom Forms 0
R How to force Outlook to use plain text in notes for Contacts? Using Outlook 1
G Outlook Express (DBX) to Outlook (PST) Conversion Software Wanted Using Outlook 1
J Outlook 2016 Can't display some embedded HTML images in Outlook 2016 Using Outlook 2
J Outlook EAS protocol version Using Outlook 1
N Outlook 2021 'Run Script" Rules? Outlook VBA and Custom Forms 4
C Why does Outlook (desktop) 365 for Windows keep making me input my passwords? Using Outlook 8
P Comcast IMAP broken but their second level support said to call "the Outlook company" Using Outlook 4
bdsermons Outlook 365 command button in outlook form Outlook VBA and Custom Forms 5
B iCloud telling me my Outlook is not supported Using Outlook 2
cheapfaremart Which outlook version is best? Using Outlook 0
T Outlook 2021 Cannot open attachments Outlook DeskTop 2021 Using Outlook 0
M Outlook settings will not accept a password Using Outlook 9
C Outlook FROM ADDRESS -Outlook.com and Android Using Outlook 1
E Outlook 365 Outlook/VBA Outlook VBA and Custom Forms 11
O How to find and replace a word in Outlook-Agenda-Subject and Message? Using Outlook 0
gproston Why doesn't Outlook remember indexing? Using Outlook 1
X Open Hyperlinks in an Outlook Email Message (Help with Diane's solution) Outlook VBA and Custom Forms 3
J Outlook 2003 .pst Will Not Restore Completely to Outlook 2019 Using Outlook 5
R Outlook Logging Using Outlook 6
e_a_g_l_e_p_i Email notifications changed with Outlook 2021 Using Outlook 8
Y Disable Microsoft Outlook Test Message Using Outlook 5
J Outlook 365 Outlook 2016/365 Contacts Lose Info when Favorited to the To-Do Bar Using Outlook 2
Commodore Are newer versions of Outlook still "less secure" to Google? Using Outlook 22
Commodore Any way to create "from-only" account on Outlook 2021? Using Outlook 1
Z Outlook.com OST Stopped working without explanation Using Outlook.com accounts in Outlook 3
glnz How to retrieve or redo Verizon.net email password without affecting Outlook connection? Using Outlook 1
S New Outlook Appointment - Select All Body Text and Change Font and Size Outlook VBA and Custom Forms 1
V Outlook 2021 Outlook-2021 (64-bit) and iCloud-for-Windows v13.0 - It Works Good. Using Outlook 9
O Outlook 365 - Gmail and Outlook: how to force Outlook to start up in Gmail? Using Outlook 2
M Seeking PDF Recommendation for Outlook that retains links Using Outlook 7
J SCANPST errors Outlook PST repair? Using Outlook 1
L did MS ever add way to text via Outlook Using Outlook 5

Similar threads

Top