Hi. I am having a similar problem. Since updating to 10.9.5 finder does not work. it starts, displays whatever directory it happens to be in, and will display the first directory you click. then it is done. You can't close it, can't display a different directory, and the display window picks up whatever is on top of it (if you happen to open a window over it) and never refreshes. I do use google drive and a 3rd party add on called insync but i've been using them for a long time and only on this update did finder become an issue. Below is the system data fromt eh program mentioned above. thanks.
EtreCheck version: 1.9.15 (52)
Report generated September 25, 2014 at 4:07:43 PM CDT
Hardware Information: ?
MacBook Pro (Retina, 15-inch, Early 2013) (Verified)
MacBook Pro - model: MacBookPro10,1
1 2.7 GHz Intel Core i7 CPU: 4 cores
16 GB RAM
Video Information: ?
Intel HD Graphics 4000 - VRAM: (null)
NVIDIA GeForce GT 650M - VRAM: 1024 MB
Color LCD 2880 x 1800
S27D390 spdisplays_1080p
LCD TV spdisplays_1080p
System Software: ?
OS X 10.9.5 (13F34) - Uptime: 0 days 6:54:30
Disk Information: ?
APPLE SSD SD512E disk0 : (500.28 GB)
S.M.A.R.T. Status: Verified
EFI (disk0s1) <not mounted>: 209.7 MB
Macintosh HD (disk0s2) / [Startup]: 499.42 GB (421.8 GB free)
Recovery HD (disk0s3) <not mounted>: 650 MB
USB Information: ?
PHD 3.0 Silicon-Power 1 TB
S.M.A.R.T. Status: Verified
EFI (disk1s1) <not mounted>: 209.7 MB
Chris Doerfler Back Up Drive (disk1s2) /Volumes/Chris Doerfler Back Up Drive: 999.86 GB (17.63 GB free)
Apple Inc. FaceTime HD Camera (Built-in)
Apple Inc. Apple Internal Keyboard / Trackpad
Apple Inc. BRCM20702 Hub
Apple Inc. Bluetooth USB Host Controller
Microsoft Natural® Ergonomic Keyboard 4000
Burr-Brown from TI USB audio CODEC
Brother HL-5370DW series
Thunderbolt Information: ?
Apple Inc. thunderbolt_bus
Elgato Systems Thunderbolt Dock
Gatekeeper: ?
Mac App Store and identified developers
Launch Daemons: ?
[loaded] com.adobe.fpsaud.plist Support
[running] com.insynchq.insync.daemon.plist Support
[running] com.lobotomo.IPSecuritasDaemon.plist Support
[loaded] com.microsoft.office.licensing.helper.plist Support
User Launch Agents: ?
[loaded] com.google.keystone.agent.plist Support
User Login Items: ?
iTunesHelper
Google Drive
ScanSnap Manager
Insync
Internet Plug-ins: ?
FlashPlayer-10.6: Version: 15.0.0.152 - SDK 10.6 Support
QuickTime Plugin: Version: 7.7.3
Flash Player: Version: 15.0.0.152 - SDK 10.6 Support
Default Browser: Version: 537 - SDK 10.9
SharePointBrowserPlugin: Version: 14.4.4 - SDK 10.6 Support
Silverlight: Version: 5.1.30514.0 - SDK 10.6 Support
SlingPlayer: Version: (null) - SDK 10.8 Support
JavaAppletPlugin: Version: 14.9.0 - SDK 10.7 Check version
Audio Plug-ins: ?
BluetoothAudioPlugIn: Version: 1.0 - SDK 10.9
AirPlay: Version: 2.0 - SDK 10.9
AppleAVBAudio: Version: 203.2 - SDK 10.9
iSightAudio: Version: 7.7.3 - SDK 10.9
iTunes Plug-ins: ?
Quartz Composer Visualizer: Version: 1.4 - SDK 10.9
3rd Party Preference Panes: ?
Flash Player Support
Time Machine: ?
Time Machine not configured!
Top Processes by CPU: ?
2% WindowServer
1% Google Chrome
1% fontd
0% coreaudiod
0% coreservicesd
Top Processes by Memory: ?
262 MB WindowServer
164 MB Dock
164 MB com.apple.IconServicesAgent
147 MB Google Chrome
147 MB Mail
Virtual Memory Information: ?
44 MB Free RAM
3.80 GB Active RAM
11.03 GB Inactive RAM
1.12 GB Wired RAM
2.32 GB Page-ins
7 MB Page-outs