MS 365 Office, Outlook (Classic) - How to save Account Individual Large Sub-folders, my Account has got so large & is too slow to operate efficiently?

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MS 365 Office, Outlook (Classic) - How to save Account Individual Large Sub-folders, my Account has got so large & is too slow to operate efficiently?

John B. Gandalf 20

MS 365 Office, Outlook (Classic) - How to save Account Individual Large Sub-folders,

my Account has got so large & is too slow to operate efficiently?

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etc

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MS Outlook (Classic) recovers my emails from my .@ntlworld.com and

VirginMedia will soon be ceasing their service and I need to protect my emails.

When I get them all saved somewhere (Example on my own NAS System) I can then sort out,

in my own time, what I want to keep and delete.

Thank you. John.

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Answer 1

Kai-H 30,315 Microsoft External Staff Moderator

Hi, John Blair Gandalf

You can save each monthly folder shown in your screenshot as a separate Outlook Data File (.pst), including attachments. Exporting creates a copy, so it will not reduce your mailbox size by itself.

Here are some suggestions you can try:

Wait until Outlook has downloaded all the emails you want to save.

Select File > Open & Export > Import/Export.

Choose Export to a file > Outlook Data File (.pst).

Select one monthly folder, check Include subfolders, and select Next.

Save it to your computer with a recognizable name, such as Emails-January-2025.pst, then select Finish. Repeat for the other folders.

My recommendation is to open each backup in Outlook and check the messages before deleting any originals. Close Outlook before copying the backups to your NAS. Keep the NAS copies for storage only, and copy them back to your computer when needed. Opening PST files directly over a network can cause performance problems or corruption.

Kai-H 30,315 Reputation points Microsoft External Staff Moderator

2026-10-26T08:11:37.9233333+00:00

Hi, John Blair Gandalf

It has been a while and I am writing to see how things are going with this issue.

Have you had a chance to check the replies provided?

Any update would be appreciated.
John B. Gandalf 20 Reputation points

2026-10-29T13:09:59.0166667+00:00

KH, Thanks for the answer / help. I will give that a go and see that I manage to save my files and therefore my emails. Can I keep this open for now till I am happy with the process, then I will close this off as then I would not have any more questions. Many thanks. J Blair.
John B. Gandalf 20 Reputation points

2026-10-30T12:05:13.97+00:00

solutions does not seem to work, plse help more if possible tks.
John B. Gandalf 20 Reputation points

2026-10-30T12:14:03.8933333+00:00

Plse help more thanks
John B. Gandalf 20 Reputation points

2026-10-31T16:35:11.96+00:00

Sorry this 3rd place I've put comment / answer. will summarize here as the first I don't seem to see it anywhere !!

Saved .pst file when opened in MS CLASSIC Outlook shows EMPTY / NO EMAILS !!

Plse help more tks.
Kai-H 30,315 Reputation points Microsoft External Staff Moderator

2026-11-01T09:01:34.8433333+00:00

Hi, John Blair Gandalf

Thanks for the screenshots. They show that your emails haven't been lost.

The #EMAILS 2016 folder in your Outlook Data File shows 4817 next to it, so Outlook counts 4817 unread items in that folder.

The .pst file is about 426 MB. An empty data file would only be a few hundred KB.

At the bottom left of the Outlook window, the status bar says "Filter applied".

So the messages are there, but a view filter is hiding them. Your earlier screenshot showed only 2 of 4817 emails in the original folder, which points to the same filter. It was most likely carried over with the folder's view settings.

To show the emails again:

Click the #EMAILS 2016 folder in the Outlook Data File.

Go to the View tab and click Reset View. If Outlook asks for confirmation, click Yes.

If they still don't appear, go to View > View Settings > Filter and click Clear All, then OK twice.

Make sure the All tab is selected above the message list, not Unread.

The "Filter applied" text at the bottom should then disappear, and your messages should be listed.

If that doesn't work:

Go to View > Change View and pick Compact or Single, then click Reset View again.

Type a word you know is in one of those emails into the search box. Set the scope to Current Folder or All Outlook Items. If results come back, the emails are definitely in the file and only the view needs fixing.

As a last resort, close Outlook. Press Windows + R, type outlook.exe /cleanviews, and press Enter. This resets all custom views to the default. It doesn't delete any emails, but any custom column layouts will be lost.
John B. Gandalf 20 Reputation points

2026-11-02T09:06:43.7133333+00:00

Kai, Thaks for that - will try those instructions to see if that reveals the emails that I hope are saved in that .pst file. I'll advise outcome hopefully later today 02Nov26. Thank You. John B.
John B. Gandalf 20 Reputation points

2026-11-02T09:12:20.4766667+00:00

Kai, Oh by the way I only screenshot'ed two of the emails (protecting my personal email data information) in that screenshot where you said quote "So the messages are there, but a view filter is hiding them. Your earlier screenshot showed only 2 of 4817 emails in the original folder, which points to the same filter. It was most likely carried over with the folder's view settings." You may be correct about filters and carrying annything over into the saved .pst but I've never knowingly used any filters in all my email workings. FILTERS - this is a new area for me as I don't know anything about filters and the use of them. Tks. John B.
John B. Gandalf 20 Reputation points

2026-11-02T10:22:18.7833333+00:00

Kai, MAGIC the filter instructions resolved my issue. Note original now changed from 4817 to shows 4822 msges All set to Unread screenshot 'One'.

Followed your instruction to QUOTE

"Go to the View tab and click Reset View. If Outlook asks for confirmation, click Yes.

If they still don't appear, go to View > View Settings > Filter and click Clear All, then OK twice.

Make sure the All tab is selected above the message list, not Unread.

The "Filter applied" text at the bottom should then disappear, and your messages should be listed."

Not sure where this part QUOTE

" Make sure the All tab is selected above the message list, not Unread."

came in as did not observe this but anyway issue resolved.

Outlook Data .pst file successfully cleared filters issue to also show now 4822 msges all changed to unread as by screenshot 'Two'.

Thank you for concealing my email name and protecting me in this respect. Learnt something more there so hopefully obliterated my email name / identitiy as necessary in attached 2 x jpg's confirming resolution.

Last statement & question - this my first interaction through this medium requiring help and it resolved my problem so if and when I come down this avenue again for help and in order to clear wasted time between comments is there anyway I would know that more details have been added that I need to come back into what I understand as my MS Learn account to action and progress rather than wait until the next time I go in to action therefore saving lost time day or days between comments / discussions. Regards John B.
John B. Gandalf 20 Reputation points

2026-11-02T10:40:56.1466667+00:00

Kai, MAGIC the filter instructions resolved my issue. Note original now changed from 4817 to shows 4822 msges All set to Unread screenshot 'One'.

Followed your instruction to QUOTE

"Go to the View tab and click Reset View. If Outlook asks for confirmation, click Yes.

If they still don't appear, go to View > View Settings > Filter and click Clear All, then OK twice.

Make sure the All tab is selected above the message list, not Unread.

The "Filter applied" text at the bottom should then disappear, and your messages should be listed."

Not sure where this part QUOTE

" Make sure the All tab is selected above the message list, not Unread."

came in as did not observe this but anyway issue resolved.

Outlook Data .pst file successfully cleared filters issue to also show now 4822 msges all changed to unread as by screenshot 'Two'.

Need to understand and read up about "Filters" now as seems I use them for my Outlook presentation and therefore need to understand filter impacts when saving all my emails.

Thank you for concealing my email name and protecting me in this respect. Learnt something more there so hopefully obliterated my email name / identitiy as necessary in attached 2 x jpg's confirming resolution.

Last statement & question - this my first interaction through this medium requiring help and it resolved my problem so if and when I come down this avenue again for help and in order to clear wasted time between comments is there anyway I would know that more details have been added that I need to come back into what I understand as my MS Learn account to action and progress rather than wait until the next time I go in to action therefore saving lost time day or days between comments / discussions. Regards John B.

Screenshot 'One'

Screenshot 'Two'

Thank you.
Kai-H 30,315 Reputation points Microsoft External Staff Moderator

2026-11-03T08:41:55.2966667+00:00

Hi, John Blair Gandalf

Great to hear the messages are back, and thanks for posting the update with screenshots. It'll help anyone else who runs into the same problem.

About the "All tab" step: it's the All | Unread switch just above the message list. You can see it in both of your screenshots. All was already selected for you, so that step didn't apply. I included it because if Unread is selected, Outlook shows only unread messages and the folder can look half empty.

About filters: lots of people never set one on purpose. A filter can get turned on by accident, for example by clicking a column header option or Filter Email on the Home tab. It can also come across with a folder's view settings when the folder is moved or exported. One more thing: your first screenshot (the original folder) still shows"Filter applied" in the bottom-left corner. Everything looks fine now, but if you want to clear it, select that folder and go to View > Reset View.

About privacy: your email addresses are well hidden. The second screenshot does still show your first name in the "To" column and a full name in one of the message previews. If you'd like to remove those, you can edit your post and replace the image.

About getting notified of replies: you can set up email alerts for your questions in your Microsoft Learn profile settings (Change your Microsoft Q&A preferences):

Sign in, click your profile picture at the top right, and choose Settings.

Scroll to Manage email preferences, enter the email address where you want notifications, and click Save.

Under Q&A preferences, turn on Q&A email notifications.

Under Q&A follow preferences, tick Follow questions you've asked.

Under the email notification options, turn on the alerts for new answers and comments (set them to Instant if that option is shown), then click Save.

For a question you've already posted, you can also open it and click Follow in the Activity sidebar. If no emails arrive after that, check your Junk folder.

If this answer helped, please consider marking it as accepted so others with the same issue can find it.
John B. Gandalf 20 Reputation points

2026-11-04T14:24:17.75+00:00

Kai, Well I've Tried all Sorts of ways for editing the details above and every time I try to save my next screen says save not allow or saving loses the edits ?? How Frustrating !! Tried deleting the jpg's in previous with a view or adding back in ones I've edited directly on my Laptop but can't delete them !! Can you edit for me as you have done before. I've got two other copies security edited as best I could I may add in here again and if you can tidy that up for me I'd be grateful for that.

I have been in my settings of my account and hopefully sorted the idea on notifications to me, thanks for that info. you mentioned steered me in the right direction. If I can get the secutity ideas finalised and sorted all I need to do is sign off this chat dialog as all info good and resolved my issues if I haven't already signed it off as completed. Plse advise thanks John B.

ScreenShot One

ScreenShot Two
Kai-H 30,315 Reputation points Microsoft External Staff Moderator

2026-11-05T06:41:40.5433333+00:00

Hi, John B. Gandalf

Sorry the edit kept failing. I've removed all your personal information in the earlier screenshots from your post, so they're no longer visible. You don't need to try editing it again.

I've checked the two new copies you posted, and you did a good job masking them. Glad the notification settings are sorted too. From now on, you should get an email whenever someone replies to your question.

Thanks for your patience, and all the best.
John B. Gandalf 20 Reputation points

2026-11-05T15:30:11.97+00:00

Kai, Well that all done then and I've hopefully Marked your answer to my question as ACCEPTED. Many tks for all your help and responses. All Appreciated so I'll say good bye for now till, if ever the next time. Rgds J.B.