Microsoft Excel Troubleshooting is a course in fixing common Excel problems, such as data turned into dates, wrong formula results, colleagues entering unrealistic values or deleting formulas, broken links between files and slow workbooks, with shortcuts that get work done faster. It suits regular Excel users, staff who build reports and anyone refreshing the basics before advanced Excel.
People who use Excel every day tend to hit the same problems again and again. Frequently used commands take several clicks, codes starting with zero lose their zeros, numbers turn into dates, formulas disagree with the calculator, colleagues enter unrealistic values or delete formulas by accident, every file asks about links when it opens, or a workbook grows so large that it opens slowly. These problems have causes that can be found, and most can be fixed with tools already in Excel.
This course gathers the problems most often met in Excel in Microsoft 365 and works through them one by one: program settings, automatic data conversion, entering data in many cells at once, checking formulas with the formula auditing tools, shortening formulas, data validation, highlighting and selecting cells by condition, custom number formats and Thai digits, protecting formula cells, summarising across sheets with 3-D references and Consolidate, and on to links between files and slow workbooks. It finishes with a workshop that repairs a real problem file. (2 days, 6 hours per day, 12 hours in total, Intermediate level.)
Course Details
This is the 2026 edition of the Microsoft Excel Troubleshooting course. It runs for 2 days, 6 hours per day, 12 hours in total (09:00-16:00), as lectures with labs, at Intermediate level. It keeps the original topics of the Quick Access Toolbar, program defaults, entering data in many cells, checking formulas, data validation, custom number formats, Thai digits, cell protection, 3-D references, Consolidate and spelling out numbers, updates every procedure for Excel in Microsoft 365, and adds automatic data conversion settings, Evaluate Formula, LET, Allow Edit Ranges, the Workbook Links pane, Check Performance and TRIMRANGE. Learners take home a table of symptoms and fixes, practice files with answers and sample number format codes.
Section 1: Lab: Setting Up Excel for Your Work
Section 2: Lab: Fixing Data Entry and Conversion Problems
Section 3: Lab: Entering Data in Many Cells and Sheets at Once
Section 4: Lab: Tracking Down Wrong Formula Results
Section 5: Lab: Shortening Formulas So They Are Easy to Maintain
Section 6: Lab: Controlling Data Entry with Data Validation
Section 7: Lab: Highlighting and Selecting Cells by Condition
Section 8: Lab: Custom Number Formats and Thai Digits
Section 9: Lab: Protecting Formula Cells
Section 10: Lab: Summarising Across Sheets with 3-D References and Consolidate
Section 11: Lab: Fixing Links Between Files and Slow Files
Section 12: Workshop: Repairing a Problem Excel File
No public rounds are open right now. Join the waiting list and we will contact you first when the next round opens, or ask us on LINE. Or call 02-570-8449 or 088-807-9770
Select all the cells first. If they are scattered, hold Ctrl and click each one. Then type the entry and press Ctrl+Enter, and it goes into every selected cell without bringing any formatting with it. To fill only the empty cells, use Go To Special and choose Blanks first, and to enter data on several sheets at once, group the sheets.
Every cell in Excel starts out locked. Select the cells people should fill in and clear Locked on the Protection tab of Format Cells, then turn on Protect Sheet on the Review tab with a password. Formula cells can no longer be changed, but the input cells still work. To let different people edit different ranges, use Allow Edit Ranges.
Excel converts data automatically when an entry looks like a number or a date, so it drops leading zeros, rounds numbers longer than 15 digits or turns some codes into dates. In Excel in Microsoft 365 on Windows you can turn off each conversion under File, Options, Data in the Automatic Data Conversion section, or format the column as Text before entering or importing the data.
It suits people who use Excel regularly and keep running into the same problems, administrative, finance, accounting and HR staff who build reports in Excel, and anyone refreshing the basics before Excel database or advanced formulas courses. You should know Windows and have used Excel for everyday work for a while, such as entering data and writing SUM or IF formulas.
You will be able to set up Excel and the Quick Access Toolbar for your work, prevent unwanted data conversion, enter data in many cells at once, check and fix wrong formulas, shorten formulas, restrict what can be entered, highlight cells by condition, format numbers including Thai digits and amounts in words, protect formula cells, summarise across sheets and fix files with broken links or slow loading. Participants who complete the training receive a Certificate of Completion with its own number, which can be verified online.
Yes. It can be run in-house for your team, with examples adapted to your own work, such as solving problems from the Excel files your team actually uses. You can request a quotation from this page, or contact us on LINE @itgenius or by phone on 02-570-8449.
Articles are published in Thai.
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