The question that opens this thread is one we hear constantly from people who have outgrown the solo spreadsheet. You have built a Sales Dashboard that works, you are proud of it, and now you are about to open the door to a team that will, through no malice of their own, find ways to break it. The instinct to lock everything down is understandable. The deeper truth is that protection and collaboration are not opposing forces; they are two sides of the same design problem. When you share a file, you are not just sharing data, you are sharing a system of logic. The real task is to make that logic resilient enough to survive contact with other humans.
Your first concern, preventing users from overwriting formulas while still allowing data entry, is the classic tension. Sheet protection is the obvious answer, and it works, but it often creates a brittle experience. You end up locking cells, unlocking input ranges, and then praying that no one uses Paste Special. A more practical approach is to separate the input layer from the calculation layer entirely. Put the raw sales entries on a dedicated input sheet, and keep your KPIs and dashboard visuals on a separate, protected sheet that references that input. This is not about being controlling; it is about creating a clear boundary between what is data and what is logic. If you are still fighting with these issues in a traditional desktop file, you might find that the real bottleneck is not the users, but the tool itself. The same way Excel not filtering unique values can frustrate a simple task, the architecture of a shared workbook often creates the very fragility you are trying to prevent.
This brings us to your second question, which is the more strategic one. You are at a fork: keep it in Excel with OneDrive or SharePoint, or move to a dedicated web app or BI tool. Here is our honest take. If you stay in Excel, you are signing up for a lifetime of patching. You will become the accidental system administrator, constantly checking version history, managing co-authoring conflicts, and explaining why someone's number does not match the dashboard. The cloud does not fix the fundamental issue; it just makes it easier for more people to break it faster. We have seen this pattern repeatedly in our community, from Power Query help spitting data from a column into multiple new column to the everyday struggles with Problem with the Paste function in Excel 2021. These are symptoms of a tool that is being stretched beyond its intended design. A dedicated web app or BI tool gives you a database, a permission model, and a controlled interface. That is not a luxury; that is the baseline for any serious multi-user environment.
The practical takeaway is this: do not ask how to protect a spreadsheet. Ask whether you should be using a spreadsheet at all for this purpose. If you need to lock down formulas, that is a sign that the logic is too fragile to trust. If you need to worry about intentional overwrites, that is a sign that you need an audit trail, not a password. For a sales dashboard with multiple users, a BI tool or a low-code app is not a bigger commitment; it is a smaller one, because it removes the need for constant manual oversight. The moment you stop protecting cells and start designing for shared logic, you have moved from managing a file to building a system. That is the shift worth making. Watch for the moment when you spend more time on access control than on analysis; that is the signal that your architecture, not your users, is the problem.