For four days I have been unable to open a lot of documents. When I try I get a message "The document "name" could not be opened. You don't have permission. This has happened to an important letter which I corrected four times. My Mac has altered the name

Question

This problem began when I typed in an address http www etc., making one mistake in the address. I corrected it and then tried to copy the address because it was long (I wanted to be able to acces it another time), and that's when the trouble starrted. I just copt documents to get a new one because it's quicker, but it is unorthodox, I know. Since then whenever I copy a document i cannot open it, and it often puts a gobledegook ending to the document name. I've started emailing texts to myself so as to keep them, but I MUST be able to use documents normally. I hava a MacBook Pro, using OS Mountain Lion 10.8.5. I don't like it. It's fairly new, and has messed up my system of documents : the size is alll wrong and the tabulations are worse than ever. I use text edit because I wanted to use Macdictate because I am handicapped (arthritis and firbomyalgia) but I have never been able to get it to work. Since I changed OS I cannot use Text edit properly any more. Please help me. I think it must be a bug that came through when I was putting this address in four days ago. I went to the site once I'd corrected the address and it was perfectly normal. I shall ring them today and ask them if this has happened to anyone else. I live in France. Thank you for your advice. Because I am handicapped and I do not dirve, it is very difficult to get to a Mac store. I deleted Mac cloud documents because I don't want to use it and I thought it might solve the problem, but it didn"t.

Answer 1

Back up all data.
This procedure will unlock all your user files (not system files) and reset their ownership and access-control lists to the default. If you've set special values for those attributes on any of your files, they will be reverted. In that case, either stop here, or be prepared to recreate the settings if necessary. Do so only after verifying that those settings didn't cause the problem. If none of this is meaningful to you, you don't need to worry about it.
I've tested these instructions only with the Safari web browser. If you use another browser, they may not work as described.
Step 1
If you have more than one user account, and the one in question is not an administrator account, then temporarily promote it to administrator status in the Users & Groups preference pane. To do that, unlock the preference pane using the credentials of an administrator, check the box marked Allow user to administer this computer, then reboot. You can demote the problem account back to standard status when this step has been completed.
Triple-click anywhere in the following line on this page to select it. Copy the selected text to the Clipboard (command-C):
{ sudo chflags -R nouchg,nouappnd ~ $TMPDIR.. ; sudo chown -R $UID:staff ~ $_ ; sudo chmod -R u+rwX ~ $_ ; chmod -R -N ~ $_ ; } 2> /dev/null
Launch the Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.
Paste into the Terminal window (command-V). You'll be prompted for your login password. Nothing will be displayed when you type it. You may get a one-time warning to be careful. If you don’t have a login password, you’ll need to set one before you can run the command. If you see a message that your username "is not in the sudoers file," then you're not logged in as an administrator.
The command will take a noticeable amount of time to run. Wait for a new line ending in a dollar sign (“$”) to appear, then quit Terminal.
Step 2 (optional)
Take this step only if you have trouble with Step 1 or if it doesn't solve the problem.
Boot into Recovery. When the OS X Utilities screen appears, select
Utilities ▹ Terminal
from the menu bar. A Terminal window will open.
In the Terminal window, type this:
res
Press the tab key. The partial command you typed will automatically be completed to this:
resetpassword
Press return. A Reset Password window will open. You’re not going to reset a password.
Select your boot volume ("Macintosh HD," unless you gave it a different name) if not already selected.
Select your username from the menu labeled Select the user account if not already selected.
Under Reset Home Directory Permissions and ACLs, click the Reset button.
Select
 ▹ Restart
from the menu bar.