FLS Checker plugin

That is very handy - thank you.

Many thanks for this, very useful!! I recently posted a long article about the subject on the gearslutz forum, explaining the need for visualization of the remaining FLS slots and also describing a work-around strategy, you can find it on the lower half of this page (almost at the end of the page):


One question, could you also make a 32-bit VST2 version of this plugin? As I described in that article I am using the 32-bit process as an additional resource for FLS slots, and I would like to be able to see the number of slots in that process… thanks in advance!

reason 9.5 - 82 slots
sonar x3e - 107
reaper - 117
live 9 lite - 86

It looks iike 9.5 is a step in the right direction. Now we can visually see it perhaps we should figure out what plugin vendors consume the most FLS and hit them up with people power?

Please follow the link as mentioned in my previous post yesterday, you will find there an extensive FLS test for most of the common plugins as well as a work-round strategy for the FLS limitation.

It’s good to get these numbers out in the open. Steinberg is going in the right direction, but we as users definitely need to push the plugin vendors to reduce their slot usage!! UAD and Arturia are my biggest culprits, on average taking up between 2-4 slots per plugin. Whereas Waves uses only 2 no matter how many plugins you use.

I found a way of gaining a few extra slots as well. Drag and drop the plugin onto the Cb icon on desktop and you I always get extra slots over opening Cubase and then opening the project from the Hub. It seems that on my system the Hub takes 6 slots itself (after opening the hub and I see the free slots go down).


I think you can remove the hub and free up FLS by moving it out of Steinberg/Cubase9.5/Components folder. You can move some other stuff out of there too so long as your not using it

Thanks very much for the tool Takashi!
Also thanks lucas for sharing this valuable info. A must read really.

For me in Cubase 9.5.20

95 Slots (FLS VST3)

8.0 - 89
8.5 - 89
9.0 - 88
Sometimes values changes by -+1 (dont know why :slight_smile: )

Thank you for this tool!

Thanks a bunch for this. Very kind and generous of you.

  • Cubase 9.5.20 84

  • Sonar Platinum 2017.10 114

  • Ableton Live 10 110

  • Reason 10 66

  • Wavelab Elements 9.5.20 110

  • Finale 25.5 100

This was on Windows 7 SP1 x64

Cubase AI 9, Win 8.1 = 97

Cubase 9.5.20, win7 110

After removing items not used from Steinberg Components folder. That gave approx. +10 FLS

That’s quite a difference from what I got! My measurement was in an empty project with just one FX track. I’m new to Cubase and haven’t explored what’s in the Components folder (and I’m on the train to work now); could you give an idea of some of what you were deleting, please? Effects, instruments, other? Thanks.

Cubase 9.0.40 -> 69
Control Room off -> +2
using Onboard Soundcard (actually turning off the hardware integration for the UR242 in the mixer I guess) -> +8

Cubase 9.5.20 -> 78
Control Room off -> +2
using Onboard Soundcard -> +8

Ableton Live 10.0.1 -> 109

Quoting Fabio from an older post
"…For the time being, those who have the problem can lower the amount of loaded dlls by moving some of the components out of the folder C:\Program Files\Steinberg\Cubase 9\Components. Of course, this applies only to the dlls which are not needed during use (eucon if you don’t use such controllers, video files if you don’t need video support, hubservice, etc - make sure to not remove any core component like Baios, the exception dumper, mediaservice, SamplerTack, stepdesigner and the VST files). This will allow for more plug-ins… not much more, but could help some of you.

euconadapter (support for Euphonix / AVID controllers)
hubservice (Steinberg Hub, without this, you will only see the Project Assistant, the Hub on the left will be missing)
omffilter (you will be unable to import OMF files)
video (all files, of course all video features will be missing)

Of course make sure you don’t use any of these features

Great. Thanks for the info. I can get rid of some of those that I’ll never use. I might keep the hub for now.


It will only disable the internet part of the hub not the browsing projects and setup part

I’m sorry but what is fls mean? It’s not amount of CPU threads ,is it?

FLS = Fiber Local Storage. It’s not really necessary to know what it means (I don’t) but only to understand that in MS Windows there are a maximum of 128 FLS Slots per process, and with respect to this discussion, Cubase takes up some slots itself then each unique plugin (VSTi or FX) can take up one or more slots within the Cubase process as well. Therefore there is a hard limit to the number of unique plugins that you can utilise in Cubase. I say ‘unique’ plugins because only the first instance of any plugin takes up the slots, after that you can use that same plugin as many times as you like.

I have problems because I have quite a large collection of plugins which I like to use within all my project (e.g. UAD, Soundtoys bundle, Arturia bundle, etc.).

It’s not one plugin per slot because some plugins take more than one slot, and the worst one I’ve found is Arturia AnalogLab2 which will take up 28 slots. Waves is the best for me because it takes up only 2 slots ever no matter how many plugins I use.

The 128 limit was designed by MicroSoft and it’s been there for many years. It looks very unlikely it’ll change so it’s down to the software developers to find ways around the problem. I personally think it’s only really come to light recently because Steinberg have dropped the 32bit bridge and therefore all plugins now take up slots on the main Cubase process as opposed to say 1/2 the plugins taking slots in the 32bitBridge process (at least, that’s what I’m seeing in my setup).

It effects every DAW not just Steinberg, and Steinberg have recently reduced the number of slots Cubase takes for itself so they’re being pro-active in trying to help the situation. They say this is done by dynamically linking the DLLs instead of statically linking them. Plugin manufacturers can do this as well, and some are doing this faster than others.

Hopefully the more noise about this subject then the more the developers will streamline their software in future updates to help avoid the limit.