Locking down a worksheet should be a straightforward promise: protect the sheet, and the data you've secured stays put. But this reader's experience reveals a frustrating gap in that promise. They did everything right, unprotected the sheet, added their new columns, set one to remain locked and the other to stay open for input, then re-enabled protection. The original cells obeyed. The unlocked range they specified stayed unlocked. But every single new column defaulted to unlocked, silently undermining the entire point of the protection exercise. That's not a user error; that's a system behaving in a way that feels like a trap.
Here's what's actually happening, and it's worth understanding because it changes how you should approach protection in a mixed-mode environment. When you protect a worksheet, the protection applies to the *existing* cells at that moment. New columns or rows added afterward don't inherit the "locked" status of their neighbors, they come in with the default formatting, which in most spreadsheet applications is "locked." But the reader is working in browser mode, and there's a known quirk: the browser version doesn't always respect the same cell-formatting defaults as the desktop app, especially when protection is toggled on and off. So even though they carefully set the unlocked range in the Manage Protection window, the new columns slipped through because the browser treated them as brand-new cells with no protection assignment at all.
The practical takeaway is blunt: you cannot assume that re-enabling protection will retroactively secure new columns. You have to explicitly select those new columns, open the cell formatting options, and set them to "locked" *before* you turn protection back on. That's the step that was missed here. The reader did check the desktop app to ensure all cells were locked, but the browser session likely didn't sync that formatting choice for the new columns. It's a workflow trap that catches people who move between interfaces, and it's exactly why testing your protection after every structural edit, not just trusting the toggle, is non-negotiable.
This isn't about dismissing the reader's frustration; it's about arming yourself with the right mental model. Protection is not a one-time state; it's a live condition that requires you to reassert your intentions every time you change the structure of the sheet. If you're adding columns, treat it like a mini-audit: select the new cells, confirm their lock status, then re-protect. And if you're primarily in the browser, don't assume the desktop settings carry over without checking. The tools are powerful, but they reward a deliberate, hands-on approach. So before you call it done, click into those new columns, verify their protection, and then lock the sheet down. That extra minute will save you from the quiet erosion of control that this reader just lived through.