Microsoft JET Database Errors

In the last few weeks we have seen some new specific errors reported by JCS users. These errors occur intermittently when attempting to read or write to a Microsoft JET database over a network, as JCS does. We are aware similar problems have been reported by other users of Microsoft JET databases, particularly since December 2019.

In JCS, the errors tend to most frequently occur during start up or when performing Bulk Valuations, but may occur in other areas too. The errors are:

  • 3046 - Could not save; currently locked by another user
  • 3260 - Could not update; currently locked by user ‘UserName’ on machine ‘PCName’
  • 3531 - The wait period for an event has timed out
  • 3043 - Your network access was interrupted. To continue, close the database, and then open it again.
  • 3035 - System resource exceeded

These errors are not caused by a specific version of JCS and, as yet, we have not been able to link them to a particular Microsoft Windows or Office update. Unfortunately we have not been able to reliably reproduce these errors in our test environments either. There has been some speculation among our users that these errors started occurring after updating to the new version of the database used by JCS (JCS Version 30.100.04 and later). We can confirm that this is not the case and installing an earlier version of JCS will not solve the problems. The working assumption by Microsoft at the moment is that changes they made to the locking system within the Microsoft JET system to help address the issue of databases corrupting have caused this problem. It appears these changes have been brought in various updates since December 2019.

Please help us

We are now working with Microsoft to try and diagnose and help them fix these problems, but we do need help from you all in doing so. Please whenever you have an error in JCS submit the error to us by clicking on the “Send Error Details to JCS” button. This helps us identify under what circumstances the errors are occurring. This information will enable us to assist Microsoft, so that they can hopefully fix the problem more quickly.

The error details you submit are encrypted before transmission but if you have any concerns about your privacy, please refer to our Privacy Policy.

We would like to apologise for any inconvenience caused by this ongoing problem. If you have any questions, please feel free to contact our technical support on 03450 049 599 opt 1 or at This email address is being protected from spambots. You need JavaScript enabled to view it.


Error 3340: Query is corrupt error

There is a serious bug in the Microsoft Office Patch Tuesday update which was released yesterday (12th November 2019) which prevents JCS and other Microsoft Access software from working.

This update is currently rolling out worldwide and will prevent you from being able to use JCS at all. We have created this advice rapidly in the last hour and advice may change as we understand the issue more thoroughly. 

To fix this problem you need to reverse out part of the update depending on which version of Office you use for JCS and which version of Windows you are running. If you do not have this problem yet you need to stop the update from installing.

We have had confirmation from Microsoft that this will be fixed again in the next Patch Tuesday release on 10th December 2019, so in the meantime you need to make sure that the problem patch is not applied.


Office 365 and 2019 versions of JCS

Windows 7-10

 If you have not yet had the issue:

  1. Open an Office app, such as Word.
  2. Create a new blank document.
  3. Click on File.
  4. Click on Account.
  5. On the right side, click the Update options menu.
  6. Select the Disable Updates option.


 If you have the issue:

  1. Download the Office Deployment Tool.
  2. Install and extract it to a covenient location such as your desktop and copy into a folder named ODT. This folder should now contain a file called Setup.exe and a couple of other xml files.
  3. In the ODT folder, right click, select New and create a New Text document naming it RevertOffice.txt. Open this file and copy the following text into it, replacing the xxxxx's with the correct version number as below:


<Updates Enabled="FALSE" TargetVersion="16.0.xxxxx.xxxxx" />


Where xxxxx.xxxxx is

  • 12026.20320 for retail versions of Office 2016 C2R and Office 2019 
  • 10351.20054 for volume licensed versions of Office 2019 
  • 12130.20272 for Office 365 Version 1910
  • 11328.20438 for Office 365 Version 1902
  • 10730.20386 for Office 365 Version 1808

Save this text file and rename it RevertOffice.xml.

  1. In Windows, click Start, search for cmd, right-click Command Prompt, click Run as Administrator.
  2. Switch to the file location for the Setup.exe file. For example, type “cd C:\Users\User Name\Desktop\ODT” (Nb: replace User Name with correct name). 
  3. Run the following command: “setup.exe /configure RevertOffice.xml”
  4. Open an Office app, such as Word.
  5. Click on File.
  6. Click on Account.
  7. Click the Update options menu and select Enable Updates from the dropdown list.
  8. Click on Update Now, Office will take a few minutes to download the files
  9. Check if Office has reverted to your targeted version by checking the file > account. It should have reverted to the version you entered in the RevertOffice.xml file.
  10. Now in Update Options, disable Updates
  11. JCS should now start up without errors.


Office 2016 versions of JCS

If you have not yet had this issue:

Windows 7/8

  1. open Windows Update. You can easily find it by entering Windows Update in the Start menu search.
  2. Select Change Settings
  3. Uncheck Receive updates for Microsoft products and check for new optional Microsoft software when I update Windows checkbox


Windows 10

  1. Open Settings, and click/tap on the Update & Security icon.
  2. Click/tap on Windows Update on the left side, and click/tap on the Advanced options link on the right side.
  3. Turn off the Receive updates for other Microsoft products when you update Windows or Give me updates for other Microsoft products when I update Windows option


If you are having the issue

Windows 7, 8

  1. Go to Control Panel
  2. Select Programs
  3. Select Programs & Features
  4. Select View Installed Updates
  5. Select the update (Office 2016 KB4484113) and click uninstall.
  6. open Windows Update. You can easily find it by entering Windows Update in the Start menu search.
  7. Select Change Settings
  8. Uncheck Receive updates for Microsoft products and check for new optional Microsoft software when I update Windows checkbox


 Windows 10

  1. Go to Control Panel
  2. Select Programs
  3. Select Programs & Features
  4. Select View Installed Updates
  5. Select the update (Office 2016 KB4484113) and click uninstall.
  6. Open Settings, and click/tap on the Update & Security icon.
  7. Click/tap on Windows Update on the left side, and click/tap on the Advanced options link on the right side.
  8. Turn off the Receive updates for other Microsoft products when you update Windows or Give me updates for other Microsoft products when I update Windows option

 If you have any queries please do not hesitate to call Tech Support on: 03450 049 599 Option 1.



Workflow - Progress Update

Over the last few months we have been busy working on a suite of new features for JCS, which we plan to release by the end of 2019. “Workflow” is a broad term, meaning different things to different people, so here is an overview of what to expect in the initial Workflow release:

  • The Workflow system is implemented by creating “Tasks” which are the individual elements (‘to do’) of each Workflow.
  • It will be possible to create templates of Tasks, which are called “Workflows”. At any time, a user will be able to select from a menu of these Workflows to initiate a pre-defined sequence of Tasks.
  • These Workflows may be a linear sequence of Tasks (where one Task starts after a previous Task is completed), a group of Tasks, which can be pursued simultaneously, or any combination of the two. The rules of Workflow templates will allow for a great deal of flexibility of Task progression, which will be able to model all real world scenarios.
  • There will be a new concept in JCS: “Groups”. It will be possible to assign JCS Users to any number of Groups and you will be able assign Tasks to either individual Users or Groups. Users will be able to find Tasks which have been assigned to them personally but also Tasks which have been assigned to Groups of which they are a member.
  • It will be possible to look at Tasks from the “higher” level of Workflows, to see which Workflows are in progress and what their status is. You will be able to drill down to see which Tasks in a Workflow have been completed, which Tasks are currently in progress and which Tasks will be created in the future when the current Tasks are completed.
  • When upgrading to the Workflow system, Diary Reminders will automatically be migrated to “Tasks”. It will be easier to find Tasks which are outstanding, which are linked to particular Client or Case, or which are assigned to a particular JCS User.

After the initial release of these features we intend to continue to develop Workflow in JCS. Depending on demand, this may include enhanced reporting, greater automation of commencing Workflows, or integration with third party software.

We will soon be in a position to offer pre-release demonstrations of the features described above. If you would like to have a sneak preview then please contact us.

Client Production Summary Report

In the latest JCS version there is a new report, which we are sure will be of interest to many of our users.

The Client Production Summary report gives an easy-to-digest overview of the financial value of clients to your practice. In just a few clicks you can see a summary of records from the Sales Ledger, Time/WIP Ledger, Commission Receipts Ledger and Disbursements Ledger, within any date range, arising from any client in your dataset.

As well as working for individual clients, the report can total the figures for all clients of a particular Adviser and/or all clients of a particular Client Code.

If you would like us to add filters to the report options, so you can use the report for additional groups of clients, then please get in touch.



Important Upgrade to JCS

Over the past few months, our Development team have been working on a major upgrade to JCS, which is now available for download.

If you have already installed the March 2019 release of JCS (version 28.101.08), you will immediately notice it has an updated look and feel, with a new colour scheme and high-definition font, suitable for 4K monitors.

A new modern ribbon interface has replaced the drop down toolbars at the top of the main window. You can now easily access all the various JCS features with a couple of clicks of the ribbon. 

Initial feedback from early adopters has been very positive and are confident that it will soon become second nature to all our users.  As always, we welcome feedback and of course, we will consider any suggestions you might have to further improve navigating around the software.

Part of the “Home” tab of the JCS ribbon, with easy access to the most commonly used pages

As well as these more obvious changes, a lot of work has been going on behind the scenes to keep JCS up to date with the latest Microsoft Office features and security updates.

The last few months have also been particularly busy for our Tech Support, who on top of their usual work, have had to assist several clients with a number of issues related to recent Microsoft Office and Windows updates:

Unrecognised Database Format

This issue affected some users of JCS who had not updated the software for a couple of years. After installing a particular Windows update, they were unable to start JCS, which would report an “Unrecognised database format” error. This particular problem has been resolved for all users of JCS.

Disk I/O Errors

This error, which can occur at random times whilst using JCS, is also caused by recent Windows updates. We are hopeful Microsoft will soon provide a permanent fix for this issue, but in the meantime, they have recommended a particular workaround. If you think you have been affected, please call JCS Tech Support who will be able to assist in installing the workaround.

Mail Merge Problems

This problem can affect users of Word 2013 and earlier. When attempting to perform a mail merge, after selecting a source, Word will shut down and fail to complete the mail merge. This problem can be caused by installing JCS version 28.101.08 (or higher), which uses Microsoft components incompatible with these older unsupported versions of Word. There is a simple workaround for this problem: convert the source .xlsx file to a .csv before attempting the mail merge. As Microsoft no longer offer support for Office 2013 we also are unable to fully support it, therefore we recommend that you upgrade to a later version of Microsoft Office.

Considerations Before Upgrading JCS

As with most major upgrades to software, the latest version of JCS does require more computer resources (RAM) that previous versions. 

Before installing, we recommend

  • You confirm with your IT that you have enough RAM available (minimum 2GB)
  • Microsoft Office 2016 or later. If you use Office 2013 or earlier and perform mail merges on the same PC as running JCS, please check you are happy with the workaround detailed above
  • Minimum screen resolution of 1280 x 800

The latest version of JCS is available here: