A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hello NY,
Sorry for the inconvenience you’re experiencing. From your description, Thai characters in Excel worksheet tab names appear much smaller than English characters, although they return to a normal size while the tab is being renamed.
So far, there does not appear to be a confirmed user-side fix at this time. As a temporary workaround, try opening the workbook in Excel for the web and check whether the tab names display normally there.
You could also use System Restore (if possible) to return Windows to a restore point created before the problem began.
Note: System Restore does not require a previous file backup, but Windows must already have created a restore point from before the issue began. It rolls back system files, drivers, settings, and installed programs without normally affecting personal documents or photos. However, I still recommend copying all important files to another drive before proceeding.
If the issue continues, I recommend reporting it directly from Excel by selecting File > Feedback > Report a Problem. This sends the report and diagnostic information to the relevant product team. Include the screenshots, your Windows version, and the full Office version shown under File > Account > About Excel. Although feedback does not guarantee an immediate solution, it can help bring the issue to the product team’s attention for further investigation and future improvements.
Since this is a user-to-user support forum, moderators, contributors including external Microsoft employees cannot directly intervene in Microsoft product features or access back-end systems. Our role is limited to providing technical guidance on reported issues, requests, or ideas.
Hope this could help a bit. Thank you so much for your patience and your understanding!
Best regards.