Causes and solutions for / to -2147217913-Conversion failed when converting date and/or time from character string error for sites in New Zealand
Microsoft recently introduced a change in Windows 11 (24H2) and Server 2025 that affects the English (New Zealand) regional settings, specifically altering the abbreviation for September from "Sep" to "Sept". This change was made to align with international localization standards (CLDR), but it has caused compatibility issues with many existing systems that rely on the traditional "Sep" format. The update impacts date formatting across various applications, including POS, databases, and scripts that use the dd-MMM-yyyy format.
This change in abbreviation will cause serious issues across the majority of POS functions that rely on dates and cause extreme data loss/corruption and/or stop POS from functioning altogether. Affected areas we have identified are; saving items to tables, Customer account transactions, generating a report that references September. Furthermore features such as the Dashboard and Activity Log also rely on dates and will fail when referencing data that includes September.
Unfortunately, Microsoft implemented this change without providing a fallback or compatibility option, resulting in unexpected behavior in v7.1 through to early v9 builds. The most straightforward workaround is to switch the system region to English (Australia), which retains the expected "Sep" abbreviation and avoids the issue entirely.
This issue affects all v7, v7.1 and v8 builds in addition to early v9 builds (build 8 and lower) of IdealPOS. We have been patching v9 over the last few months to handle this change in region behaviour, upgrading the site to v9 build 9 as a minimum will resolve the issue without any changes to region settings needed. At present, the issue only affects Windows 11 and Server 2025, but we cannot guarantee that Microsoft won’t extend this change to Windows 10 in future updates.
If you are unsure if this will be an issue for your site/system or not, copy and paste the following line into Powershell;
(Get-Culture).DateTimeFormat.AbbreviatedMonthNames[8]
If the result is 'Sept' instead of 'Sep' the following steps must be followed:
Step 1: Disable Location Services
Open Settings (Win + I)
Go to Privacy & Security > Location
Toggle Location services to Off
Step 2: Keep Time Zone Set to New Zealand
In Settings, go to Time & Language > Date & Time
Make sure Set time zone automatically is Off
Check Time zone and current time are still correct for you location
Step 3: Change Region to Australia
Go to Settings > Time & Language > Language & Region
Under Country or region, change from New Zealand to Australia and Regional Format to English (Australia)
Restart to apply all changes and then confirm that time is correct and abbreviation has been changed.
To confirm the change has been made, open Powershell and copy the following line in;
(Get-Culture).DateTimeFormat.AbbreviatedMonthNames[8]
The result should now be 'Sep'
Whilst this change in abbreviation only affects Windows 11 and Server 2025 at the moment we recommended setting all terminals/computers at a site to the Australia region for consistent behaviour and to handle any possible future changes to Windows 10.
If you need any further assistance or clarification with this solution please reach out directly to support