Office 365 fails every time on power up

Ian Stone 20 Reputation points
2025-11-03T13:47:23.07+00:00

For years Office 365 was working file on a Windows 10 machine.  This machine eventually expired.  It was replaced with a new Dell OptiPlex All-in-One Plus 7420 running Windows 11pro.  I am not the user of this machine, it belongs to the Tenbury Agricultural Society, a charity.  It is installed in their office, used twice a week for about 3 hours

Every time it is powered up office 365 applications fail to load, timer icon just sits there spinning.    As far as I can ascertain it is powered down correctly.

I have run all the diagnostics software which gives a good result, done a clean re install of windows 11 and other software twice to no avail.   I have carried out the re-installs in my house.  As a test I have repeatedly powered the machine up and down and it works fine there.  Each time I return it to its working site it initially works fine, Office 365 behaves then on a subsequent power up Office 365 fails.  All that’s different is the power up and down is several days apart and where it is installed, the physical location, internet service provider etc.   A  laptop running win 10 for example works fine on the same site.

Any clues as this is doing my head in.

Microsoft 365 and Office | Other
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  1. Richard Trinidad 4,475 Reputation points Independent Advisor
    2025-11-03T17:47:30.35+00:00

    Hi Ian, since Office 365 works fine at your home but fails at the charity’s office, it’s likely a network-related issue possibly the ISP, DNS, or firewall blocking Microsoft services needed for Office 365 to authenticate or sync. Try connecting the PC to a mobile hotspot while at the office to see if it loads properly. That will help confirm if the local network is the culprit.

    let me know how it goes.

    Chard

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  1. Richard Trinidad 4,475 Reputation points Independent Advisor
    2025-11-03T15:47:55.4166667+00:00

    Hi Ian, thanks for posting here in Microsoft community, it sounds like you've done a thorough job troubleshooting already. Since the issue only occurs at the charity's office and not at your home, it strongly suggests that something in the local environment like the network setup, DNS, or firewall might interfere with Office 365's ability to authenticate or connect to required services.

    One possibility is that the ISP or router configuration at the charity's location is blocking or delaying access to Microsoft services.

    Office 365 apps often need to validate licenses or sync settings on startup, and if they can't reach the necessary endpoints, they may hang.

    Also, have you tried connecting the Dell OptiPlex to a mobile hotspot or different network while at the charity's office to see if Office 365 loads properly in that environment? This could help confirm whether the issue is truly network related.

    I hope this helps you out, let me know how it goes.

    Chard

  2. Ian Stone 20 Reputation points
    2025-11-04T15:27:41.6233333+00:00

    Hi John,

    You were spot on. It was the Internet connection. Worked fine using a hotspot from my phone. The downside was the 3 hours banging my head against a brick wall talking to British Telecom support. I finaly hung up before I had a nervous breakdown. I am now looking for a decent ISP.

    Many thanks

    Ian

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