Support » Plugin: W3 Total Cache » CSS/JS Minify Cache Error

  • I logged into my WordPress Dashboard today and the following error popped up:

    Recently an error occurred while creating the CSS / JS minify cache: File “/home/gracessw/public_html/wp-content/themes/style.css” doesn’t exist.

    How do I correct this?

    I noticed my Google Page Speed score dropped drastically after replacing WP Super Cache with W3 Total Cache I’m wondering if I’ve set up the plugin incorrectly and this may be the reason for the error as well as the drop in score. My host has also initiated memcached is there a resource available to how the plugin should be setup?

    My site is

Viewing 10 replies - 1 through 10 (of 10 total)
  • The error may be due to several factors.

    The 2 most common are:

    – You are using dynamically generated CSS, like some famous themes do (Athaualpa), those are hard to cache and unless you know what to do you are just better excluding them from the minification list.

    – You just upgraded something and that something does not use that CSS any more. This happens after WP gets an upgrade and many plug ins get their own upgrade to stay current. In that case you may safely just go to minify and remove the CSS reference from the list.
    Of course you should also check the minification assistant (help button) and see if it finds new CSS and javascript files.
    If you don’t do that, over time you get more and more of those files not being minified by W3 TC and this causes a gradual worsening of your page loading times and consequently a worse YSlow score.

    As for the memcached thing, there are tutorials out there, I may even write one myself in the future.

    You have to get the appropriate info to feed into the W3 TC configuration window for memcache(d) to work. You have to ask for that info to your hosting provider.

    I.e. this screenshot is a memcached working configuration I have set up on a Varnish + memcached + APC + Nginx + WP server I have recently set up. It scores A both on Page Speed and YSlow and is good for up to 8M views a day.

    Thank you so much for the detailed response although most of it has gone over my head.

    I haven’t added anything new to my site and it seemed to be working fine until today. I updated WordPress the other day but I would assume that I would’ve received the error right way, no?

    Where do I locate the minification assistant button because I looked for it today and couldn’t find it (it was referenced in the help section).

    My hosting company suggested I switch WP Super Cache but unfortunately they could not help with the settings although they did set up memcache for me.

    My memcached settings appear to be the same as the sample you’ve provided but there are a few other boxes on my page, i.e Ignored query stems and Reject query words: When I was referencing the memcached, I meant how do I set up the W3 Total Cache to go with memcached. Do the plugin owners not list recommended settings anywhere?

    I don’t know what to do now, I might have to switch back to WP Super Cache because I haven’t a clue how to set this up, way too complicated for me.

    1) No, you wouldn’t. These errors only come up:

    – When you explicitly empty the caches and W3 TC for any reason (usually just because somebody uses the website ;P ) needs to regenerate the cached content. Since W3 TC won’t cache the WP admin, you could use WP for days without noticing any error. By default it takes a random, not logged in user to use the site to cause the full cache-ing.

    2) For an updated tutorial about how to find the button you need and how to use the whole stuff, please refer to this thread of mine: Illustrated tutorial on how to fix many plug ins that W3 TC breaks

    3) About memcached: the defaults listed in those boxes are good enough to get you started so I did not include them in the screenshot.
    You just need an IP address (usually either or your host’s IP) given to you by your hosting company and a port number. That too has to be given to you by your hosting company.

    Basically, you just slam those two numbers in the way shown in the screenshot and you are done with the memcached configuration.

    Notice that some tutorials will tell you to also use memcached for other stuff. Don’t. Some functionalities are best served by APC, others by simple “Enhanced disk cache”.

    If you optimize your website well and use APC + memcache (and possibly Varnish) you should get at least B rating both on Page Speed and YSLow.

    More tricks to raise score are: to use SmushIt add on, to use the add on that automatically adds missing ALT clauses to images and .htaccess or nginx rules to strip javascript & CSS versioning and cookies.
    A CDN is not a bad idea either, I have got good results both with Cloudflare / MaxCDN and self hosted CDN on a domain I created for it.

    Good Morning,

    I tried clicking on your tutorial but unfortunately the page is not loading.

    Is there a resource for setting up W3 Total Cache? There are a bunch of different options and I haven’t a clue where to start? I believe the memcached settings are fine because my hosting company set those up but they can not provide any information for setting up the plugin.

    Should I be installing Smushit then too for best use of the W3 Total Cache plugin?

    Sorry if I keep repeating myself, I think I’m missing what you’re trying to explain to me.


    I just checked the tutorial page and it loads just fine. Sadly it’s on a host that is not exactly a bolt.

    As for resources, you might want to check this one out. It’s fairly complete, albeit not exactly for the total beginner. By the way mine is more complete for minify settings, try loading it again a couple of times.

    Smushit is not for W3 TC but for ranking. It re-compresses your pictures as you upload them (there’s also an option to recompress already loaded stuff) so YSlow complains much less.

    There’s also a wagon load of other advice to improve ranking and rating but it’d take me 20 hours to explain them and I am quite in demand to do paid work on WP / W3TC so I may only devote my spare time to help here.

    I’ve took the manual road, and it seemed like every java script from my theme could not be minified as it seems like it breks slider, widgets, etc etc… so i unchecked all my THEME scripts and now JS minify is active and working like a charm…

    Still testing it out, but i think that everything is good now

    Some themes have a “deploy” or “production” switches, others directly implement pre-minified files. In both cases as I wrote in that tutorial linked above, W3 TC WILL try to re-minify them and WILL break them. So you’ll have to leave them out. Since they are already minified you’d not get any benefit anyway.

    Good Morning

    @dfumagalli do you offer setup services? The errors are increasing and I really don’t know what to do.



    I don’t know how to contact you about solving your issue, as I believe WP has no PM system and forum rules are against posting personal emails and similar.
    Anyway this is my “experiments and hobby” website, please contact me on this form.

    Good Morning dfumagalli,

    Unfortunately the errors continued and more popped up so I had no choice but to remove the plugin because I have so little experience and I couldn’t find any guidance for the recommended settings.

    I appreciate all your help and while I’m disappointed that I had to remove it I think it’s best at least until I become more knowledgeable in this area of WordPress.


Viewing 10 replies - 1 through 10 (of 10 total)
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