Video Clips (.mov) & (flv )

For some reason, I have recently updated a couple of codec programs, I now have a couple of folders containing the above video types that will not now play in Windows Media Player.
Any suggestions would be appreciated.

Re-installing the codec pack should fix it.

Tried That, still coming up with the message " windows cannot access the specified device, path or file".
They will play in Media Player.

Read this page:
https://support.microsoft.com/en-us/kb/2669244

Most common cause is anti-virus not working correctly.

These don't seem to apply to my problem. I have quite a few folders with different video formats.
Those that have wmv, avi & mp4 there are no problems to play them in windows media player. It is the two folders with the Video clips .mov & flv that are the problem. They are not corrupted, as I said they will play in other players.
I have just updated the K-Lite codec pack, but even that does not solve the problem.

It isn't codec related. This specific error is related to access permissions.

1) Right-click on file > Properties
There might be a "unblock" button. Windows sometimes blocks files that have been downloaded from Internet.

2) What happens if you copy one of those files to another folder?

There were some videos in each folder that were blocked. I have unblocked them all and even restarted the computer, but no change.
I moved one over to another folder and it still came up with the same message.

Another development, which should give me the answer.
As the folders were on an external storage device I decided to test it on my laptop.
Lo and behold they play without problem on Windows Media Player.
So the problem is somewhere in my PC. Any ideas?

Right-click on a file > Properties > Security > Advanced > Owner
Could be a user account from another PC. In that case change it to own account.

But strange that the problem only affects WMP.

I'm afraid that is not the answer. As in the other folders on this external device My Pc is the owner.
I'll have to go back to the original point that these are the only folders that have Video clips .mov & .flv.
I have even got a couple of MP4 videos in these folders and they play OK in Windows Media Player.
So this is telling me it is a format problem and not the folder or owner problem.

You would get a different error if it was related directly to the format itself. They would also not play after copying them to the computer.

Do these files have something else in common? Perhaps a specific tool was used to download them?

If you Google for the exact error message (with quotes) then you get a lot of results. Might include something you haven't tried yet.
"windows cannot access the specified device, path or file"

What happens if you rename one of those files to .mp4?

Well amazingly they play when I change them to mp4.
Now I need a quick fix to change over 200 files to mp4 in one movement.
Individually this is going to take a long time.

Renaming is easy:
1) Type cmd in the address bar of Explorer while in the correct folder. This will open the Command Prompt.
2) Type this command: rename *.flv *.mp4

But first try this:
1) Start the Registry Editor:
Start > Run > regedit.exe
2) Browse to these keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Multimedia\WMPlayer\Extensions\.flv
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Multimedia\WMPlayer\Extensions\.flv
Permissions should have value 15
Runtime should have value 7

If that was all correct then:
1) Uninstall the codec pack
2) Start registry editor again
3) Search for .flv
There should not be many occurrences if you uninstalled the pack.
4) For each instance you find, first make a backup. Right-click on the key and choose export.
5) Then delete the key (or value). This is safe to do, since there are no natural occurrences of .flv on a clean Windows install.
6) After each key, test playback in WMP. Right-click on file > Open (With). Don't worry if playback fails (due to missing codecs). Just test if the original error message is gone.
7) If it gets fixed, then copy the contents of the backup file here.