There's a moment of quiet absurdity in this problem that deserves attention. A brand new blank workbook opens instantly, but the moment it's saved to your local system and reopened, it drags like molasses. The file itself hasn't changed. The formulas haven't multiplied. The data hasn't grown. Yet the performance collapses. That tells us something important: the lag isn't about the spreadsheet. It's about where the spreadsheet lives and what happens the instant it becomes a resident of your machine.
The user who posted this did everything right in terms of surface-level fixes. Co-pilot is off. Autosave is off. Background error checking is off. Those are the usual suspects, and clearing them changes nothing. That's the clue. When a blank file becomes sluggish purely because it has been saved locally, the problem isn't in the workbook's content. It's in the relationship between the application and the file system. Local saves trigger background processes that cloud-native workflows simply don't touch. Indexing, thumbnail generation, file history snapshots, antivirus scans, even the way the operating system maintains metadata for recently accessed files, all of these can pile onto a simple save and turn a lightweight file into a slow-motion experience.
Here's what this means in practical terms. If you're experiencing this, stop treating it as a spreadsheet configuration issue and start treating it as a storage architecture issue. Move the file off your local drive and into a cloud-synced folder, or better yet, work directly in a browser-based workbook where the file never truly "saves" in the traditional sense. The moment you stop forcing the local file system to manage every keystroke, the lag often disappears. That's not a workaround. That's a genuine rethinking of where your work should live. The cloud isn't just about access or collaboration. It's about removing the hidden overhead that local storage quietly imposes on every open and every save.
The deeper takeaway is simpler and more useful. If a blank file becomes slow after saving, your machine is telling you something about its own background behavior. Listen to it. Don't chase settings that don't address the root cause. Instead, change the environment. Save to a location that doesn't trigger the same local indexing and scanning routines. Test it. If the same blank file stays fast in the cloud but slows down on your desktop, you've found the culprit. That's not a mystery anymore. That's a diagnosis. And once you have a diagnosis, you can stop guessing and start working again.