Your answers to frequently asked questions

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OAK Version

Which is the latest version of OAK?

From the 6th May 2022, new customers will be offered OAK version 5.4.005. After the release of 5.4.004 with a new set of utility tools, a new module for Shortcuts, improvements on the dynamic arrays compatibility and a combined per-user / machine-level installer the latest update, 5.4.005, now offers the possibility to Compare two worksheets of the same workbook as well as comparisons between workbooks with a different number of sheets.

The latest update can be downloaded from here:

I've got an earlier version of OAK. How is the latest version different?

The latest version of OAK (version 5) was launched on the 1st of July 2020 and represents a major change to the previous version – OAK 4.

OAK 5 is now a subscription based software with a completely refreshed user interface, significant performance improvements and a new feature – the Formula Walker – which allows users to easily navigate across formulae precedents and dependents as well as creating bookmarks with comments on any of the investigated cells.

OAK 4 license holders that wish to upgrade will have a 25% discount on the 1st annual subscriptions (campaign running until 31/05/2022) .

Nevertheless, we still support our OAK 4 users by fixing reported bugs but no further development will be carried out on OAK 4.

A version history that sets out the differences between revisions to OAK 4 and OAK 5 is set out in the online help document.

I've got an earlier version of OAK. What do I have to do to get the latest version?

If you have version 5 of OAK, it will alert you to the appearance of a new update and ask for your authorisation to download and install it without any upgrade costs as your subscription includes all updates and versions.

If you have version 4 or earlier of OAK, it will alert you to the appearance of a new update and ask for your authorisation to download and install it. But you will need to subscribe an OAK 5 plan if you want our latest version.

The automatic updating feature built into OAK may be prevented from working by your firewall security software. In such circumstances you should download the latest OAK5.msi file and double click on it to install the upgrade. You may need help from your IT department to do this.

Will OAK work on the Apple Mac?

OAK 5 is a Windows-only application, and will not work on the Apple Mac, unless you run it in Windows using virtualization software such as VMWare Fusion or Parallels Desktop, with the Windows version of Excel. We do not officially support this.

Does OAK work in 32-bit and 64-bit Excel?

Yes. The single OAK5 msi file installs OAK and registers it for use in both 32-bit and 64-bit Excel.

Authentication and Log in

Which email address should I use to log in on my OAK add-in?

If you bought a single OAK subscription you must use the same email address as the one on the checkout page during the purchase.

If you acquired multiple OAK subscriptions (by setting a quantity > 1 on the checkout page) then you will receive an order confirmation email (where you will have a link to download OAK) and an invite to create an account on our Operis Hub as the ‘License Manager’.

Once completed the registration, the Hub offers a ‘Manage OAK Subscription’ link to offers management tools for your orders and licenses – this is where you can assign / unassign the OAK end users, including yourself as an end-user. You can then access OAK using your email address.

When trying to log in, I keep getting the message “Unable to contact the OAK subscription server.”

If you are getting this message then we strongly advise you to update to the latest version (OAK/Account/Check for updates) as your current version is a 5.0.x which relies on our legacy licensing sustem and not the most recent one.

The message is the result of your system preventing OAK from reaching the OAK subscription server to validate your subscription. If there is some sort of firewall on your IT infrastructure, that access will be denied.

Please make sure that your computer can reach the following address:

If you’re using any version 5.1.x or above then the exceptions that you need to add to your firewall rules are the ones mentioned on the next question.

I have installed OAK, can see it on my Excel but my login credentials are not working

Your windows Firewall settings are not authorizing OAK to make external calls. To authorize OAK on your Windows Firewall please follow the procedures below:

1) Type firewall into the Windows Start box and select “Allow an app through Windows Firewall”. (If this doesn’t appear, find it manually through the control panel)
2) Assuming “Operis Analysis Kit” doesn’t appear in the list of “Allowed apps and features”, click “Change Settings” and then “Allow another app…”
3) In “Add an app”, select “Browse…”, then in the directory bar at the top type “%localappdata% and press return:
When the directory resolves, navigate to “Operis/OAK5” and select “Operis.OAK.Exe”
4) Select “Add” in the “Add an app” screen, then press OK on the original “Allowed applications” screen.
You should now be able to log into OAK5.

When trying to log in, I keep getting the message “Unexpected error.”

If you are using the latest OAK 5.1.001 or higher, your OAK will try to reach the licensing server to validate your subscription.

If there is some sort of firewall on your IT infrastructure, that access will be denied.

Please make sure that your computer can reach the following addresses: on ports 80 and 443 on ports 80 and 443


Can I install OAK at the machine level and not the default per-user installation?

From version 5.4.004 the OAK installer allows the user to choose (by using the ‘Advanced’ button’) a per-user installation (which does not requires admin rights) or a per-machine installation (requires admin rights to install).

The per-machine installer will install OAK at C:\Program Files (x86)\Operis\OAK5 and not at %localappdata%\Operis\OAK5  as on the default per-user installation.

The installer will allow your IT to comply with the Center For Internet Security recommendations, as well as Microsoft.

The latest update can be downloaded from here:

My computer won't let me download OAK. What can I do?

Some companies set up firewalls to prevent employees from downloading executable files. Companies that do that will probably also prevent executable files from being sent by email, and prevent executable files that do arrive from being installed on workstations except by designated staff. Your best option is therefore to get help from your IT department.

If you wish to try yourself, you can:

  • Download in a location not controlled by the firewall and transfer it to your computer using a memory stick
  • Ask to email the file

Will OAK install in Windows 8 or Windows 10?


I downloaded OAK to my Apple Mac to use in Parallels Desktop, but the installer says the version of the file is not compatible with the version of Windows I'm running.

While we don’t officially support the running of OAK in Windows in the Parallels Desktop environment, we suggest you try downloading the installer using Internet Explorer rather than Safari.

Does OAK work on my Microsoft Office - Windows Store Edition?

Not yet. OAK only runs in the click-to-run edition of O365, not the Windows Store edition.
Check which version you have on the Office Support website


I have a computer at work and a computer at home. Can I use OAK on both of them?

If you are using OAK 5 you can login on your OAK on any device once you have installed it. But it will not be possible to have concurrent sessions with the same login name unless your OAK subscription plan has available seats (the quantity of users that you have purchased with your plan).

If you are using OAK 4 please contact Operis explaining that at any moment you could be using one computer or the other, but never both, we will enable a second activation of your serial number for the second machine.

I have switched to using a new computer. What do I have to do to get OAK to work on the new machine?

If you are using OAK 5, you just need to install OAK on the new computer (installers are available on your Operis Customer Portal) and log in with your email address and password. For other scenarios, see the item “An employee in my company no longer needs OAK. How can I transfer it to another?”

If you are using any version between OAK 4.3 and 4.4 on the old and new computer, transfer a serial number from the old computer. Then activate your serial number on the new computer.

An employee in my company no longer needs OAK. How can I transfer it to another machine?

Your OAK 5 subscription allows you to manage the users of your OAK license by accessing the Operis Customer Portal / Manage OAK Subscriptions. Here you can add, update or remove users from your OAK subscription plan at anytime and without the need to contact Operis. Just download OAK from the portal and log in with the user’s email address.

If you are using OAK 4.3 or 4.4 on the old and new computers, you would perform a serial number transfer on the old computer. Download OAK and install it on the new computer. Then activate your serial number on the new computer. If you cannot perform the serial number transfer on the old computer, send your serial number to Operis, explaining that you wish to transfer OAK to the new computer. We can deactivate your serial number for re-use on the new computer.

If you have been using OAK 4.0 to 4.2, and you have OAK 4.3 or 4.4 on the new computer, perform a serial number exchange, then proceed as for OAK 4.3 or 4.4.

If you are moving from OAK 4.0 to 4.2 on the old and new computer, please email your new product ID to Operis explaining that you wish to transfer OAK to a new computer, and also read about serial number transfers so that you can see how upgrading to OAK 4.3 or later helps you do these transfers without the delays associated with support requests.

Will my OAK version 5 work if I do not have access to the Internet?

Being a subscription-based license, OAK 5 will need to regularly check your subscription status to confirm that it is active and that there are no concurrent active sessions on the same email address. If OAK 5 fails to check the subscription server, it will start a grace period of 3 days where you can still use OAK – especially useful when travelling.

If after the grace period no connection has been made, OAK 5 will stop working until a connection to our subscription server is re-established.

Enabling/disabling OAK

How can I turn OAK off?

You can instruct Excel whether or not to load OAK through the Add-Ins Manager.

OAK has disappeared from the ribbon or menu and the COM Add-ins manager doesn't activate it. How can I get it back?

Excel has probably placed OAK in the Disabled Items list. To make it available again, the process is different in Excel 2007-2016.

First you need to go to the Disabled Items manager:

For Excel 2007, click the Office Button, then Excel Options.

For Excel 2010-2016, click the File button then the Options button.

Then for Excel 2007 to 2016, go to the Add-ins tab. Locate the “Manage” drop down box and set its value to “Disabled Items”. Click the “Go” button.

Highlight OAK in the list, then click “Enable”.

Close the Disabled Items window. You may need to re-enable OAK in the COM Add-ins manager.

Hint: This is something OAK users are fairly likely to encounter, with OAK and other add-ins. If you want to practice the process, try the following:

Activate one of OAK’s dialogs, e.g. compare workbooks, but don’t click the Compare button on the options window, just leave it there waiting for input. Then use Task Manager to end the Excel process. Then, start Excel again. You may be prompted to disable the Operis Analysis Kit – click yes. In any case, you’re likely to find that OAK has been sent to the disabled items list, whereby you can perform the above procedure to release it.

OAK has disappeared from the ribbon, menu and disabled items, and only re-installation restores it temporarily. What can I do?

While it hasn’t been confirmed, we have observed cases where it seems that OAK’s COM registrations get deleted by unknown processes on the computers of users in some IT environments. In this case, you need to ensure the IT staff make sure that their systems are configured to permit the COM registrations that OAK’s installer requires.

Managing my OAK subscriptions

Can I change my login email address or any of the users under my OAK subscription?

Upon the payment being successful on the checkout page, you will receive an order confirmation email and an invite to register on your Operis Customer Portal .

Once you complete the portal registration a “Manage OAK Subscriptions” on the main portal page you will be able to you add, update and remove users email addresses associated with your OAK subscription.

Can I cancel my OAK subscription at any time?


Your Operis Customer Portal also offers access to your subscription status and details where you can update your payment details or cancel your OAK subscription. Because annual plans are prepaid, once you cancel your OAK subscription you will still have access through the paid period.

OAK Help Resources

Make the best use out of your time. Get a comprehensive user guide in a format best suited to your needs:

Release Notes

06 May 2022 - 5.4.005

The latest version of OAK, version 5.4.005, released on the 6th of May 2022, is a minor update to version 5.4


  • Compare is now able to to compare two sheets on the same workbook/li>
  • Compare is now able to compare workbooks with different number of worksheets

07 April 2022 - OAK 5.4.004

The latest version of OAK, version 5.4.004, released on the 7th of April 2022, is a major update to version 5.3


  • New set of Utility tools (Colors, Casing, Switch Signs, Convert References)
  • New module for keyboard shortcuts
  • Improvements on the dynamic arrays compatibility
  • F1 disable key functionality
  • Combined per-user / machine-level installer

17 December 2021 - OAK 5.3.005

The latest version of OAK, version 5.3.005, released on the 17th of December 2021, is a major update to version 5.2.008.


  • Full Dynamic arrays support
  • Now uses .NET Framework 4.8
  • Aggressive optimization removed

08 October 2021 - OAK 5.2.008

The latest version of OAK, version 5.2.008, released on the 8th of October 2021, is a minor update to version 5.2.006.


  • Replaced shortcuts macro with use of keyboard events
  • Fixed redefine names UI
  • Fixed unique cell difference counts in compare reports
  • Fixed startup error logging problem where logs folder doesn’t exist
  • Added link addresses option to IOAKAPI.Summarize

23 Jun 2021 - OAK 5.2.006

The latest version of OAK, version 5.2.006, released on the 23rd of June 2021, is a major update to version 5.

Along with the changes introduced on OAK 5.1 where:
– after feedback from our subscribers where issues with the authentication mechanism were causing random logouts we have refactored the entire licensing system. OAK uses a licensing mechanism supported by a specialized provider that manages all OAK 5 authentication using the latest security standards with very high levels of service – no more random logouts 🙂
– We also redesigned the entire customer experience with a new reseller partner (FastSpring) and a new OAK hub where the customer can manage his OAK orders and licenses, with options to:

  • download invoices
  • change payment details
  • cancel the active subscriptions
  • manage end-users OAK licenses by assigning and unassigning the corresponding emails.

Existing subscribers using OAK will be asked to update on a one-to-one basis as we want to make sure that the migration between the two licensing systems will go as smooth as possible. That’s why you will not have an automatic notification to upgrade for now if you’re an existing subscriber – we plan to roll out this version until the end of February.

OAK 5.2.006 includes:

  • New ribbon section with Operis news and announcements
  • Formula Walker
    • performance enhancements by integrating the OAK parser
    • new Date and Author columns on bookmarks
    • bookmarks export in XML format instead of CSV
  • Excel’s 365 dynamic arrays are now acknowledged by OAK

There is a detailed version history of OAK in the online documentation.

2 Dec 2020 - OAK 5.0.002 minor update

The latest version of OAK, version 5.0.002, released on the 2nd of December 2020, is a minor update to version 5


  • Increased performance on the Formula Walker by using OAK own’s parser instead of Excel’s precedents tracing mechanism.
  • New column with precedent’s value on the Formula Walker
  • Enhanced subscription mechanism to reduce random logouts
  • Updates mechanism simplified now showing the startup notification just once and changing the Account icon if an update is available

Users of OAK 5 will be automatically offered the chance to install the new version by OAK’s automatic updating feature.

There is a detailed version history of OAK in the online documentation.

1 Jul 2020 - OAK 5.00.000

The latest version of OAK, version 5.00.000, was released on the 1st of July 2020.


  • New licensing model subscription-based with Monthly and Annual subscription plans
  • Constant minor and major updates without additional cost
  • Ability to suspend the subscription at any time
  • New tool – Formula Walker
  • Compare performance enhancements
  • Simplified ribbon UI
  • Map, Summarize, Compare and Search – interface using Custom Task Panes
  • Updated to .NET Framework 4.6.2

Users of prior versions of OAK 4 will be automatically notified of this new release and a link to the Subscriptions Plans pricing page will be provided.

There is a detailed version history of OAK in the online documentation.

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