A date such as 04/05 can be difficult to interpret when a computer uses an unfamiliar regional format. Before changing anything, identify the intended date from the original record. Changing how a value is displayed cannot tell you what an ambiguous original entry was meant to represent.

Record the current Windows regional format and keep an unchanged copy of a representative file. Choose sample values with a known meaning: a date whose day is greater than twelve, an amount with a decimal fraction, and a larger number with digit grouping.

Choose the scope of the formatting change

In Windows 11, open Settings, Time & language, Language & region. Regional format selects the default date, time, number and currency conventions. Microsoft documents these defaults as affecting formats used by Access; individual applications can have their own formatting rules.

For a specific symbol or date order, open the classic Region dialogue with Windows+R, enter intl.cpl and press Enter. On Formats, choose Additional settings, then the relevant Numbers, Currency, Time or Date tab. Record the old value, change the intended item and confirm the dialogues.

A regional format change has a wider scope than reformatting a single document. Avoid changing several separators and date patterns together unless the whole new convention is deliberate.

Inspect known values in the affected application

Reopen the application or document as needed; Microsoft specifically notes that Access may need its database closed and reopened. Compare your sample values with the unchanged reference.

Check the decimal position, digit grouping and the full date. For monetary records, confirm the actual currency from the record itself: a displayed currency symbol is not evidence that an amount has been converted between currencies.

Review any exported or printed result that another person will read. Use an unambiguous date presentation where the recipient’s convention may differ.

If the application still displays an unexpected format, inspect its own settings before editing source values. Keep the original file until you have verified both the intended display and the underlying meaning of the data.

Sources: Microsoft Windows regional formatting.