Imported time sheet with read only status. I find no way to set sheet writable. Some data input fields allow editing, not all. This is not file system read only status question.
How to set all fields editable?
This is because the sheet is write protected, and in this situation on cells formatted as unprotected lets edit.
Try Menu/Tools/Protect document/sheet with a blank (none) key, otherwise you need to know the key to unprotect the sheet.
You could try copying the sheet onto a new calc sheet and then seeing if you can edit it.