There's a cleaner way to handle this than manually trimming 300 columns one at a time, and the user who posted this knows it. Power Query is the right call here. Loading the entire table, selecting all columns, and applying a single trim transform will strip those leading spaces in seconds, not hours. That's not just faster, it's the kind of efficiency that makes a Friday deadline feel manageable instead of crushing.
The TRIM function works, sure, but applying it column by column across 300 columns is a grind that no one should accept as normal. Find and replace fails because it removes spaces between words, which breaks the data. The user is right to reject both. Power Query handles leading spaces precisely, leaving internal spaces intact, and it applies the transformation to every column at once. Performance concerns are reasonable with a dataset that wide, but Power Query is built for this. It processes columns in parallel, and modern Excel handles hundreds of columns without choking. The real gotcha isn't performance, it's remembering to close and load the query back to the sheet when you're done.
What stands out here is a mindset shift. The user is asking how pros handle massive cleanup jobs, and the answer is simple: stop treating each column like a separate problem. When you have 300 columns with the same issue, you don't fix them one by one. You fix the pattern. That's what Power Query does. It lets you describe the cleanup once and apply it everywhere. VBA could work too, but it requires writing and debugging code that Power Query handles with a few clicks. For a one-off cleanup under a tight deadline, the less code, the better.
The lesson isn't about trimming spaces. It's about recognizing when a repetitive manual task signals a better approach. This user is already there, they just need permission to commit to the method that scales. So commit to Power Query. Load the table, select all columns, trim, and close. Your Friday report will thank you.