Q: Can't delete Files without Password

Seems you just met the new El Capitan's system integrity protection (in short SIP, or aka rootless).

Get reassured your password is not the problem ... this is just normal behaviour in OS X 10.11

Here are more info about this: About System Integrity Protection on your Mac - Apple Support

In case you really need to access / modify something in one of those protected folders, there is a way to disable SIP, but do this at your own risk:

- restart your Mac on the Recovery volume (CMD + R during startup)

- once started on the Recovery disk, select "Utilities" from the menus, then Terminal

- in Terminal, enter the following:

    csrutil disable

- then restart; SIP is now off and you can access / modify what you wanted to.

- when you're done, I suggest that you re-enable SIP, following the same process but enetering csrutil enable

If you cannot delete files from the Desktop or the Documents folder, indeed SIP may not be the cause of your problem anyway.

Did you already tried to reset ACL on your home folder ?

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:

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.

Select the parent folder in which the problem is occurring, and then press Command-i to get information on the folder. From here, expand the Sharing & Permissions section and then report back here with what the users/groups and associated permissions are. In general, you should see something like the following for folders in your home directory:

fabi1202 wrote:

 

Thank you for your answer. But I don't understand it because I can't delete files from my desktop. When I can't delete files in an other folder, I can understand it but so I can't

I hope you can explain me,

Fabio

Did you upgrade a drive that had a previous OS X installation? Or did you do a clean install and then used Migration Assistant to import your user account?

Select one file in the Finder and press Command-I. What do you see in the Get Info window, particularly the last part about "Sharing and Permissions"?

For a normal file that you own you should see something like this:

Maybe you lack permissions for the folder containing the file, and not the file itself, as Topher suggested.

There is a way to fix all the permissions, if that is indeed the problem, but I'd rather not offer a long terminal command unless first we make sure this is the problem.

Open DiskUtility, select the disk where you have the issue (I suppose the startup disk), click the startup partition, click the FirstAid Tab.

After that try again.

If it's affecting subfolders, then you can change the permissions in this info window for the parent folder, and then use the gear menu to propagate the permissions from this folder to all items within the folder (and subfolders). Be careful you only do this for directories used for your personal files and content (ie, those you've created in your home folder), and not any that contain system files or configuration files (ie, your home folder itself, or Library folders, or Macintosh HD, or System, etc.).