OK here's the etrecheck thing. I've deleted some stuff, so now there's 114 Gb free. Maybe that's help a bit.
EtreCheck version: 2.6.6 (226)
Report generated 12/12/2015, 21:33
Runtime 2:31
Download EtreCheck from http://etrecheck.com
Click the [Click for support] links for help with non-Apple products.
Click the [Click for details] links for more information about that line.
Hardware Information: (What does this mean?)
Mac mini (Late 2012)
[Click for Technical Specifications]
[Click for User Guide]
Mac mini - model: Macmini6,1
1 2.5 GHz Intel Core i5 CPU: 2-core
4 GB RAM Upgradeable
[Click for upgrade instructions]
BANK 0/DIMM0
2 GB DDR3 1600 MHz ok
BANK 1/DIMM0
2 GB DDR3 1600 MHz ok
Bluetooth: Good - Handoff/Airdrop2 supported
Wireless: Unknown
Video Information: (What does this mean?)
Intel HD Graphics 4000
Panasonic-TV 1280 x 720 @ 50 Hz
System Software: (What does this mean?)
OS X El Capitan 10.11.2 (15C50) - Time since boot: about 2 hours
Disk Information: (What does this mean?)
APPLE HDD HTS545050A7E362 disk0 : (500.11 GB) (Rotational)
EFI (disk0s1) <not mounted> : 210 MB
Macintosh HD (disk0s2) / : 499.25 GB (114.95 GB free)
Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB
USB Information: (What does this mean?)
Apple, Inc. IR Receiver
Apple Inc. BRCM20702 Hub
Apple Inc. Bluetooth USB Host Controller
Thunderbolt Information: (What does this mean?)
Apple Inc. thunderbolt_bus
Gatekeeper: (What does this mean?)
Mac App Store and identified developers
Kernel Extensions: (What does this mean?)
/Applications/WiTopia.app
[loaded] com.viscosityvpn.Viscosity.tap (1.0) [Click for support]
[loaded] com.viscosityvpn.Viscosity.tun (1.0) [Click for support]
System Launch Daemons: (What does this mean?)
[failed] com.apple.Kerberos.digest-service.plist [Click for details]
Launch Daemons: (What does this mean?)
[loaded] StrongHelper.plist [Click for support]
[loaded] com.adobe.SC.FPFeedbackService-1.0.plist [Click for support]
[loaded] com.adobe.fpsaud.plist [Click for support]
[loaded] net.witopia.WiTopiaHelper.plist [Click for support]
User Launch Agents: (What does this mean?)
[running] com.spotify.webhelper.plist [Click for support]
User Login Items: (What does this mean?)
iTunesHelper Application (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
Dropbox Application (/Applications/Dropbox.app)
WiTopia Application (/Applications/WiTopia.app)
Spotify Application Hidden (/Applications/Spotify.app)
Other Apps: (What does this mean?)
[running] 2BUA8C4S2C.com.agilebits.onepassword-osx-helper
[running] com.apple.xpc.launchd.oneshot.0x1000000c.EtreCheck
[running] com.getdropbox.dropbox.47392
[running] com.spotify.client.53472
Internet Plug-ins: (What does this mean?)
Silverlight: Version: 5.1.20513.0 - SDK 10.6 [Click for support]
FlashPlayer-10.6: Version: 20.0.0.235 - SDK 10.6 [Click for support]
QuickTime Plugin: Version: 7.7.3
Flash Player: Version: 20.0.0.235 - SDK 10.6 [Click for support]
LogitechHarmony: Version: 2.0 - SDK 10.7 [Click for support]
Default Browser: Version: 601 - SDK 10.11
Safari Extensions: (What does this mean?)
1Password
3rd Party Preference Panes: (What does this mean?)
Flash Player [Click for support]
Time Machine: (What does this mean?)
Time Machine not configured!
Top Processes by CPU: (What does this mean?)
51% mdworker(9)
7% WindowServer
5% Spotify Helper(2)
3% Spotify
2% kernel_task
Top Processes by Memory: (What does this mean?)
562 MB kernel_task
209 MB Spotify Helper(2)
180 MB installd
172 MB mdworker(9)
152 MB mds_stores
Virtual Memory Information: (What does this mean?)
44 MB Free RAM
3.96 GB Used RAM (1.00 GB Cached)
59 MB Swap Used
Diagnostics Information: (What does this mean?)
Dec 12, 2015, 07:28:06 PM ~/Library/Logs/DiagnosticReports/Spotify Helper_2015-12-12-192806_[redacted].crash
Dec 12, 2015, 06:42:21 PM Self test - passed
Dec 12, 2015, 05:40:15 PM ~/Library/Logs/DiagnosticReports/BezelUIServer_2015-12-12-174015_[redacted].cra sh
Dec 11, 2015, 08:14:02 PM ~/Library/Logs/DiagnosticReports/BezelUIServer_2015-12-11-201402_[redacted].cra sh
Dec 10, 2015, 10:44:57 PM ~/Library/Logs/DiagnosticReports/BezelUIServer_2015-12-10-224457_[redacted].cra sh
Dec 10, 2015, 03:50:29 PM ~/Library/Logs/DiagnosticReports/BezelUIServer_2015-12-10-155029_[redacted].cra sh