Outlook 2016 will no longer open (windows 10) and the ost file is corrupt

Question

Outlook 2016 will no longer open (windows 10) and the ost file is corrupt

CatherineG 0

Outlook 2016 will no longer open (windows 10) and the ost file is corrupt. I have tried all the online help that I can find but I still cannot open my Outlook on my PC. The issue was even made worse by trapping me with also no longer being able to open ANY of my Microsoft products. I get messages that I have to install the newer 365 product. If I must then I must BUT I do not want to lose all my old email and personal folders. Fortunately I still have my gmail online for the current mail but this does not help me with my off line personal folders. I even tried bringing over my back up ost from Friday's back up along with another attempt with the previous Friday's back up. But Outlook will not open still and the ost gets corrupted every time. AND my contacts/address book is probably at risk too.

CatherineG 0 Reputation points

2025-11-03T20:47:52.2+00:00

I'm wondering if I install Outlook 2024 if I will be able to import my back up ost file & recover my personal folders.

2 answers

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CatherineG 0 Reputation points

2025-11-03T20:47:52.2+00:00

I'm wondering if I install Outlook 2024 if I will be able to import my back up ost file & recover my personal folders.

Answer 1

Dora-T 7,145 Microsoft External Staff Moderator

Hi @CatherineG

Thank you for reaching out to the Microsoft Q&A Forum.

I understand how stressful it can be when Outlook 2016 can no longer open and reports that the .ost file is corrupt, especially when you’re worried about losing your old emails and personal folders.

Please note that Outlook 2016 has reached the end of support, so we cannot reproduce the issue in our test environment. However, I’ll do my best to assist you based on the available information.

To better understand your situation and provide more accurate guidance, could you please confirm whether your Outlook 2016 account is provided by Microsoft or by another mail service provider?

Since Outlook 2016 can no longer open properly, you might consider creating a new Outlook profile to check whether Outlook is able to start with a new configuration. You can find the detailed steps in this article: Create an Outlook profile - Microsoft Support

I look forward to your response.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

CatherineG 0 Reputation points

2025-11-04T15:23:19.08+00:00

My email server is Gmail. I'm wondering if installing Outlook 2024 could I import my ost file & recover my offline personal folders and address book. See below for the error message.
Dora-T 7,145 Reputation points Microsoft External Staff Moderator

2025-11-05T10:28:57.6233333+00:00

Please note that our forum is a public platform, and we will modify your screenshot to hide your personal information in the description. Kindly ensure that you hide any personal or organizational information the next time you post an error or other details to protect personal data.

Hi @CatherineG

Thank you for the update.

Based on my research, the .ost file usually contains a local copy of data that Outlook downloads from the mail server. Your data should still be on the server, and Outlook can download it again once a new .ost file is created.

Although I don’t have the same Outlook 2016 environment as yours, I tested this on my side using Outlook 365 and couldn’t find an option to import an .ost file. It appears that Outlook might not support importing that file type.

If the .ost file cannot be opened, you might consider moving it to another folder or re-creating a new one to check whether Outlook can start properly.

You can refer to this article for more information: Open or import items from an offline Outlook Data File (.ost) - Microsoft Support

I hope this information is helpful to you.

Answer 2

CatherineG 0

I uninstalled the old Outlook 2016. I removed the old ost file. I purchased MS Office Home & Business 2024. My Word 2024, Excel 2024 and PowerPoint 2024 now work OK. BUT Outlook 2024 still throws and error (See image above). So I still cannot open Outlook 2024 (classic) on my Windows 10 PC.

Dora-T 7,145 Reputation points Microsoft External Staff Moderator

2025-11-06T08:57:08.26+00:00

Hi @CatherineG

Thank you for your resopnse.

I understand how confusing it must be that Outlook 2024 still doesn’t open even after reinstalling Office and removing the old .ost file.

Could you please confirm whether you’ve already tried creating a new Outlook profile as mentioned earlier to see if Outlook can open?

If not, please try the steps below:

-Hold Shift while starting Outlook.

-On the profile picker dialog box, select Options.

-Select New.

-Type a name for the new Outlook Profile and select OK.

-Add your Gmail account when prompted, then try starting Outlook again.

I look forward to your reply.
CatherineG 0 Reputation points

2025-11-06T14:26:55.35+00:00

Same error as noted above. But I did get in my gmail online account...

And this was created...
Dora-T 7,145 Reputation points Microsoft External Staff Moderator

2025-11-07T12:42:37.8333333+00:00

Hi @CatherineG

Thank you for your reply, and I truly appreciate your effort and patience throughout this process.

Since Outlook still doesn’t open, please try one of the following options that might help resolve the issue:

1.Rename the OST file

-Go to the folder where the new .ost file was created. It may be located in a path such as: C:\Users<YourUserName>\AppData\Local\Microsoft\Outlook

-Rename the file by adding .old at the end.

-Restart Outlook and see if it creates a fresh .ost file and opens normally.

2.Start Outlook in Safe Mode

-Right-click the Start button and select Run.

-Type Outlook.exe /safe and click OK.

Please let me know what happens after you try these steps.
CatherineG 0 Reputation points

2025-11-07T14:51:46.19+00:00

I already tried all that during the first days, to no avail. I finally gave up and went to Geek Squad who managed to get Outlook to open BUT still no personal folders. For that apparently they need more tools to recover the data and I have to lug my PC into the store. Fingers crossed that might work and I get my contacts, personal folders and my calendar back.

Curious additional event was that my Windows start up avatar image vanished during the MS online fix. Hmmm. That was rather invasive. That was when MS locked all my MS products and tried to force me to buy Outlook 365. Almost sounded like one of those hackers that takes control and demands money to unlock your computer.

Now I need to remember how I loaded the avatar and where that old image is.

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Outlook 2016 will no longer open (windows 10) and the ost file is corrupt

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