You go to open a spreadsheet and Excel tells you it is locked for editing by someone else, or that you can only open it read-only. There are three usual causes: someone genuinely has it open, someone left it open on a computer that has since gone to sleep, or the file is holding a stale lock - a note left behind after a session that ended badly, such as a laptop that lost power mid-edit.

Try this first

1. Read the name in the message and ask that person. It sounds obvious, and it resolves this most of the time. If the message says a name you do not recognise, or says another user with no name at all, skip to step 3.
2. Check it is not you. The same file open on your other computer, on a home machine, or in an Office window sitting minimised on a second screen will lock you out of your own document. Close everything Office-related on your other devices first.
3. Open it in the browser and keep working. This is the important one. Go to the file in SharePoint, Teams or OneDrive on the web, click the three dots next to the file name, choose Open, then Open in browser. The browser version of Word, Excel and PowerPoint does not use locks in the same way, so you can usually edit straight away even while someone else has the desktop app open. Your changes save into the same file, not a copy.
4. Give it fifteen to thirty minutes. A lock left behind by a sleeping computer or a dropped connection releases itself after a while. If nobody is actually in the file, waiting through a coffee often solves it.
5. If you must work offline, take a clearly named copy. Open the file read-only, then use File, Save a copy, and put the date and your name in the file name. Then tell whoever owns the document, so somebody merges your changes back in rather than discovering two versions next week. Copies are the thing that turns a five-minute problem into a two-hour one, so use this as a last resort.

If that didn’t fix it

Log a ticket and give us the full file name, which library or Teams channel it lives in, and the exact wording of the message including any name it shows. We can see who holds the lock, whether that person is actually connected, and clear a stale lock safely. We can also check whether the file has any unsaved changes sitting on someone else’s machine before we do it, which is the bit you cannot check yourself.

How to avoid it entirely

Locks are an old idea, from the days when files lived on a server in the cupboard and only one person could safely write to them at a time. Modern Microsoft 365 files do not need them, because of co-authoring - several people editing the same document at the same time, with everyone seeing each other’s changes appear.

To get co-authoring working reliably:

• Keep the file in SharePoint, Teams or OneDrive rather than on a mapped drive, a USB stick or a local Documents folder. Anything on an old file server will always lock.
• Leave AutoSave switched on. It is the toggle at the top left of Word and Excel. Co-authoring depends on it.
• Save in the current formats: .docx, .xlsx, .pptx. The older .doc and .xls formats cannot co-author, and neither can files that have a password set on the file itself.
• Close documents at the end of the day rather than leaving twenty tabs open overnight. This is the single biggest cause of morning lock messages.

If one particular file locks constantly, tell us which one. There is usually a specific reason - an old format, a linked workbook, or a macro - and it is normally a quick fix.

Still stuck?

Log a ticket at portal.yougrowit.com.au or email support@yougrowit.com.au. If it is stopping you working right now, call 03 9028 4358.

Support hours are Monday to Friday, 8:30am to 5:30pm Melbourne time, excluding Victorian public holidays.