Date entered is changed to a different date

The issue you're experiencing with Excel altering dates is likely due to regional settings or date system mismatches between your laptop and your husband's. Here's a structured solution:

Root Cause Analysis

 1. Date Parsing Conflict:
Excel interprets dates based on your system's regional settings (e.g., MM/DD/YYYY vs. DD/MM/YYYY). If your laptop uses a different format than the file expects, entering 01/01/2025 (January 1st) might be parsed as 01/01/25 (Day 1, Month 1, Year 1925) if Excel misreads the separator.

 2. 1904 Date System:
If your Excel uses the 1904 date system (common on Macs), dates are stored as days since 1904-01-01. This can cause discrepancies when opening files created with the 1900 system (Windows default). For example:

• 01/01/2025 in the 1900 system = Day 45,678.
• In the 1904 system, this becomes Day 45,678 − 1,462 (days between 1900–1904) = 44,216, which converts to October 29, 1970.

 3. Corrupted Excel Settings:
A glitch in Excel’s settings or a recent update might break date parsing.

Step-by-Step Fixes

  1. Check Regional Date Format

• Windows Settings:
  Go to Settings > Time & Language > Region > Regional Format.
  Ensure the format matches your data entry (e.g., MM/DD/YYYY for U.S., DD/MM/YYYY for Europe).
• Excel-Specific Format:
  In Excel, go to File > Options > Advanced > Use 1904 Date System and uncheck it (Windows default).

 2. Force Excel to Recognize Dates

• Format Cells as Text First:
  Temporarily format the column as Text (right-click column > Format Cells > Text).
  Enter dates with slashes (e.g., 01/01/2025), then reformat as Date.
• Use DATEVALUE Function:
  If dates are already corrupted, use =DATEVALUE(A1) in a new column to convert text to dates.

 3. Reset Excel’s Settings

• Repair Office Installation:
  Open Excel → File > Account > Update Options > Repair.
• Delete Corrupted Preferences:
  Close Excel. Press Win + R, type %appdata%\Microsoft\Excel, and delete the Excel16.xlb file (back up first).

 4. Test in a New Workbook

Create a new Excel file and test date entry:

• If dates work, the issue is file-specific. Copy data into the new file.
• If dates still break, proceed to repair Excel.

 5. Disable Automatic Conversion

• Use Apostrophe Before Dates:
  Type '01/01/2025 to force Excel to treat it as text, then reformat.
• Turn Off AutoCorrect:
  File > Options > Proofing > AutoCorrect Options > Uncheck "Replace text as you type".

Why It Works on Your Husband’s Laptop

Your husband’s laptop likely uses:

• The 1900 date system.
• Regional settings matching the date format you’re using.
• A corruption-free Excel installation.

Prevent Future Issues

• Standardize Date Formats: Agree on YYYY-MM-DD (universal) or MM/DD/YYYY (U.S.).
• Use Data Validation:
  Go to Data > Data Validation > Date, and set allowed dates to avoid typos.
• Update Excel: Ensure both laptops are on the same build (e.g., Microsoft 365 vs. 2019).

By aligning regional settings, disabling the 1904 system, and resetting Excel, the issue should resolve. If problems persist, a full Office reinstall may be needed.

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Hello iindy500​,

Excel is misreading your dates because of a mismatch between your Windows regional settings and Excel’s date system. Check your Windows Region → Regional format and make sure it matches the date style you’re using (MM/dd/yyyy vs dd/MM/yyyy).

Also confirm the column is formatted as Date in Excel. Using slashes (01/19/2026) instead of dashes helps. If it still misbehaves, run an Office Quick Repair.