How was user able to (accidentally) change an unlocked cell to loc

[J-Bo]

I gave a user a protected worksheet with a range of unlocked cells. She
edited (typed into) one such unprotected cell. At some point she also saved
the file and at one point she also had to use an autorecovered version of the
file after her computer crashed. After saving, and possibly also after the
autorecovery, she attempted to copy content from an unlocked cell and paste
it into the unlocked cell she had previously edited. She received a message
that this cell she was trying to paste to was locked. She returned her copy
of the file to me. The worksheet was still protected (she was never told and
couldn't have guessed the password, and wouldn't know how to change the cell
settings), and this cell was indeed set as locked in her copy. I looked at
the original copy I had emailed to her, and in that copy the cell was set as
unlocked. How could this setting have changed while the worksheet was
protected? Could it have simply been a weird error upon autorecovery? Or is
there possibly something I need to do to prevent it? Excel Help provides no
clues.

 

[Pete_UK]

Cells are set as Locked by default. Perhaps the cell she copied from
was Locked, and so when she pasted into the unlocked cell it then
became locked.

Hope this helps.

Pete