Mirabis

Well, if you read my response (link), you shouldn't worry. 
 
We have a stable release of StableBit CloudDrive, and we've been actively going through DrivePool bugs.   
 
Additionally, we should be going through StableBit Scanner issues as soon as we're done with that.   I'm personally upgrading to an NVMe based systems (Samsung 960), so we will have "hands on" and that will help with support.  
 
 
 
That said, we are a very small company, and have limited resources. But we specifically have plans in motion to help prevent this sort of long time between releases.  It won't happen again.  

Not a problem. It's a bit more complicated, especially as it basically requires the use of the File Placement rules:
Install the SSD OPtimizer, enable it, and configure it. Set File Placement rules for the documents, pictures, etc, selecting every disk except for the SSD drive(s).  On the Settings (main) page for the balancing, uncheck the "File placement rules respect real-time file placement limits set by the balancing plug-ins".  This tells the software to respect the file placement rules, even when they violate the real time placement limits set by the SSD Optimizer. 
 
 
If you want the File Placement Rules to keep the files on the SSD drive, regardless:
Install the SSD OPtimizer, enable it, and configure it. Set File Placement rules for the folders/files in question etc, selecting the SSD drive(s) (and any others).  On the Settings (main) page for the balancing, uncheck the "Unless the drive is being emptied".  Normally, the SSD Optimizer balancer attempts to "empty" the SSD/cache drives, clearing them out. Normally, the balancers will respect the file placement rules *except* when the drives are being emptied. Meaning it will not respect the file placement rules properly.  Unchecking this means that the file placement rule will *always* be respected, even if a balancer (including the StableBit Scanner balancer) wants to empty out the drive.      These rules are not mutually exclusive, meaning that if you want to do both, just set the rules and settings accordingly, and you can get both options. 

Try this: 
http://wiki.covecube.com/StableBit_DrivePool_2.x_Advanced_Settings
Set "CoveFs_WaitForVolumesOnMountMs" 50000, and see if that helps. 
 
 
Otherwise, you could run "services.msc", find the "StableBit DrivePool Service", right click on it and select "Properties". Then set the "startup type" to "Automatic (Delayed)", and that may help with the issue. 

The other option is to add the StableBit CloudDrive service as a dependancy for StableBit DrivePool.  However, this is a bit more complicated, and requires registry editing. 

Well, the latest betas for StableBit DrivePool should avoid using CloudDrive disks for Read Striping now.  
 
Take it for a spin.
http://dl.covecube.com/DrivePoolWindows/beta/download/StableBit.DrivePool_2.2.0.754_x64_BETA.exe

You're very welcome! 
 
If you want a guideline. check the change log. Grab the second numbered build, as this will be more stable, as the changes are set and other issues moved to.  So right now, that would be 2.2.0.753.  
 
Otherwise, if you wait, when there is a new stable release, you'll get an update notification.