How can I fix my Downloads folder?

Select the icon of your Downloads folder in the Finder (not in the Dock) and open the Info window. In the Sharing & Permissions section, does it show that you have read & write access?

Have you rebooted since this started? If not, try that now.

Please read this whole message before doing anything.

This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.

The purpose of this exercise is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login. Boot in safe mode and log in to the account with the problem. First, disconnect all wired peripherals except keyboard, mouse, and monitor, if applicable, and remove all aftermarket expansion cards. The instructions provided by Apple are as follows:

• Be sure your Mac is shut down.
• Press the power button.
• Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone, but not before the tone.
• Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).

The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.

Safe mode is much slower to boot and run than normal, and some things won’t work at all, including your login items.

Launch the application(s) and test. Same problem(s)?

After testing, reboot as usual (i.e., not in safe mode.)

Please launch the Terminal application by entering the first few letters of its name into a Spotlight search, and drag or copy -- do not type -- the following line into the window:

ls -AOel Downloads

Press return. Post the lines of output that appear below what you entered -- the text, not a screenshot.

Back up all data if you haven’t already done so. Before proceeding, you must be sure you can restore your system to the state it’s in now. If you skip this step, no one but you will be responsible for the consequences.

Copy or drag -- do not type -- the following line into the Terminal window:

rm -i Downloads/.DS_Store

The following line should appear below what you entered:

remove Downloads/.DS_Store?

If that's exactly what you get, enter "y" (without the quotes) and press return. If you get anything else, enter "n" and try again. When you have successfully entered the command, relaunch the Finder by selecting Apple menu > Force Quit... from the menu bar. Then try again to open the Downloads folder.

How you back up is up to you. Any data that you don't back up will eventually be lost, whether you follow my advice or not. Time Machine is a good backup solution. For that you need an external hard drive, not a flash drive.

The above shell command will delete the invisible file in your Downloads folder that stores the Finder's display settings for that folder. The file may be corrupt.

If you prefer not to take that step, I suggest you make a Genius appointment at an Apple Store. It's a free service. Regardless of that, you must back up your data before you do anything else.

Is there any way to back up a computer without an external hard drive?

No. There's online backup, but I wouldn't recommend that as your only backup.

Also, does data include programs and applications?

It's not absolutely necessary to back those up, but consider what it would take to rebuild your whole system from scratch.

If the invisible file is deleted, what are the effects on the performance of my Mac afterwords?

Either none, or the problem you're having will be solved.

Will I have to recreate a file to store display settings?

That happens automatically.

Do you think that an Apple support phone call would be able to solve my problem?

I don't know. Most likely Apple Support would tell you to reinstall the Mac OS, and if that doesn't help, to erase your boot volume and restore from backup.

The point here is that you have a much more serious problem -- lack of backups -- than the one you originally asked about. You need to solve the big problem before you address the lesser one. You can't meaningfully use a computer at all without backups.