Final Cut Crashes after opening! Help please!

Hello Community,

I have this awful problem with Final Cut Pro currently, were i cant open it after it crashed once in the middle of editing. I try to fix it and even went so far to delete the whole Mediathek, even the backups. And Finally i could open Final Cut again and stared importing and working again. Than after 4 or even more hours and when i was nearly finished it crashed again and i have the same problem again. Now i thought about what i was doing while it crashed again but both times it was while working with different clips and the second time around i was just writing names at the ending.
I don't know what to do from here on, i think i will try and delete and reinstall Final Cut, but really how is that any difference and how do i know whats actually the matter so it doesnt happen again?

I work on a MacBook Pro (retina, early 2013) Version OS X Yosemite 10.10.5
Prozessor 2,7 GHz Intel core i7
16 GB 1600 MHz DDR3

Here is the Crash report:

Process: Final Cut Pro [4038]
Path: /Applications/Final Cut Pro.app/Contents/MacOS/Final Cut Pro
Identifier: com.apple.FinalCut
Version: 10.2.1 (264102)
Build Info: ProEditor-26410002056000000~1
App Item ID: 424389933
App External ID: 812379208
Code Type: X86-64 (Native)
Parent Process: ??? [1]
Responsible: Final Cut Pro [4038]
User ID: 501


Date/Time: 2015-08-30 10:36:04.153 +0200
OS Version: Mac OS X 10.10.5 (14F27)
Report Version: 11
Anonymous UUID: 7C33E313-67DC-8817-7BE2-F6A5AC63CF34


Sleep/Wake UUID: CA7139A1-5A7B-4102-B1AE-2F302C7EDF72


Time Awake Since Boot: 26000 seconds
Time Since Wake: 4000 seconds


Crashed Thread: 16 BGTask: MEBackgroundLoadManager Dispatch queue: NSOperationQueue 0x608007a25d00 :: NSOperation 0x608000534e60 (QOS: USER_INITIATED)


Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000190


VM Regions Near 0x190:
-->
__TEXT 0000000103dce000-0000000103ead000 [ 892K] r-x/rwx SM=COW /Applications/Final Cut Pro.app/Contents/MacOS/Final Cut Pro




Thread 16 Crashed:: BGTask: MEBackgroundLoadManager Dispatch queue: NSOperationQueue 0x608007a25d00 :: NSOperation 0x608000534e60 (QOS: USER_INITIATED)
0 com.apple.ozone.framework 0x0000000121131696 OZSingleChannelBehavior::getChanBase() const + 6
1 com.apple.motion.TextFramework 0x00000001220392c4 TXTextInput::notify(unsigned int) + 1044
2 com.apple.ozone.framework 0x0000000120dc4108 OZNotificationManager::processNotifications() + 360
3 com.apple.Motion.effect 0x0000000120a3c1b5 -[FFMotionEffect initSceneNodesOrChannelsFromSavedEffectValues:scene:isInitSceneNode:] + 2485
4 com.apple.Motion.effect 0x0000000120a3c922 -[FFMotionEffect _makeLoadedDocReady] + 669
5 com.apple.Motion.effect 0x0000000120a3acbb -[FFMotionEffect _backgroundLoadDocument:onTask:] + 991
6 com.apple.Flexo 0x00000001046972cf -[FFBackgroundLoadManager _backgroundTask:onTask:] + 319
7 com.apple.Flexo 0x00000001050135ec FFApplicationHandleExceptionThatShouldNotBeIgnoredInBlock + 12
8 com.apple.Flexo 0x000000010473d05d -[FFBackgroundTask main] + 333
9 com.apple.Foundation 0x0000000107051b3c -[__NSOperationInternal _start:] + 653
10 com.apple.Foundation 0x0000000107051613 __NSOQSchedule_f + 184
11 libdispatch.dylib 0x000000010c2c9c13 _dispatch_client_callout + 8
12 libdispatch.dylib 0x000000010c2cd365 _dispatch_queue_drain + 1100
13 libdispatch.dylib 0x000000010c2ceecc _dispatch_queue_invoke + 202
14 libdispatch.dylib 0x000000010c2cc6b7 _dispatch_root_queue_drain + 463
15 libdispatch.dylib 0x000000010c2dafe4 _dispatch_worker_thread3 + 91
16 libsystem_pthread.dylib 0x000000010c611a9d _pthread_wqthread + 729
17 libsystem_pthread.dylib 0x000000010c60f3dd start_wqthread + 13

Any new fonts or audio plugins installed lately?