Upon opening my File Manager i receive the message
'A Problem has been detected with your thumbnail cache. Fixing it will require administrative priviliges'.

This sounds a bit odd to me.
Did anyone of you experience this before?
So my question would be:
Should i click 'fix now' or is this a virus looking for root priviliges?

(It would also be helpful knowing what a thumbnail cache is)

  • 3
    could you please say why your'e downvoting? thanks.
    – this.foo
    Sep 18, 2015 at 18:12
  • 1
    This just happened to me too but I'm running Linux Mint. This after just having read about the OS getting hacked (blog.linuxmint.com/?p=2994) makes me feel uncomfortable.
    – axiopisty
    Feb 24, 2016 at 16:04
  • @axiopisty I to had Linux mint when this had happened, but switched to Kubuntu now
    – this.foo
    Feb 25, 2016 at 17:48
  • 1
    @axiopisty Not Linux Mint got hacked, but their website. Now, after the incident, they have their servers protected behind a firewall of a professional security company. So I don't think, there are any valid security concern against using Linux Mint left now. Aug 3, 2016 at 14:25

2 Answers 2


Looks legit (enough)

In the Nemo Browser (fork of Nautilus), it's part of the official source-code:

label = gtk_label_new (_("A problem has been detected with your thumbnail cache.  Fixing it will require administrative privileges."));

Looks legit enough for me.

Alternative Fix

If you are unsure, what you could do, here's a manual fix.

By browsing the same source code file, one can see, what Fix now is actually doing.
It is just calling nemo with root priviliges using the --fix-cache argument:

sh -c "pkexec nemo --fix-cache"

If you prefer a more familiar shell command, you could instead run

sudo nemo --fix-cache

from the terminal to get your thumbnail cache fixed.


thumbnails are smaller versions of images nautilus uses to quickly display a preview when opening a folder with images (or videos) in it.

They should be in your home directory ~/.cache/thumbnails, and in my experience, can be safely deleted.

So one option would be to simply remove that directory, nautilus will then generate them again when needed.

To do so, you can open a terminal and type rm -Rf ~/.cache/thumbnails.

Of course, this will lead to some loading times until the cache is refilled.

This solution would not require root privileges.

Virusses are rare on linux, but being wary of giving root privileges is a good thing. I would not think that you have a virus, but the only way to know would be to scan. I have used clamav for that purpose in the past.

Why exactly nautilus is having this problem I cannot tell, wiser souls will have to answer this one.

  • removed directory, but the problem still seems to be there
    – this.foo
    Sep 15, 2015 at 11:19
  • well, that is strange. If I were you, I would probably click "fix it" and not worry too much. That is not to say this is the safest or best approach, it is what I would do. Or you could wait until someone comes along who can tell what is going on exactly.
    – bytepusher
    Sep 15, 2015 at 17:32

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