Problem Details:

osu can't start after installing the most recent update from the in-game updater. When launched, the osu logo fades in, stays for a few seconds, then abruptly disappears but then fades in again, stays, and disappears again. The cycle goes on forever. I'm guessing the game is crashing on start and automatically tries to restart when it crashes. When viewed in task manager, the game process takes about 135k RAM before crashing and starting again. The cycle only ends when i kill the process.

I've tried forcing to run the game in maintenance mode by creating a "help.txt", but the updater detects that the latest version of the game is installed and proceeds to try to run normally (and start the crash loop again). I've tried using a old backup of osu I have and it works. I was thinking my copy of the game is corrupted so I copied over and ran the old osu updater (osume.exe was it), and it replaced the game files with an old version. The old version (b20141008.17) works but again automatically downloaded the update files. I installed the update files and the crash loop starts again, possibly hinting that the problem lies in the new version?

-using windows 7 ultimate 64bit with .net framework 4.5(+SDK),4.5.1(+SDK),4.5.2
osu! version: 20150203.7

I am stuck in a crash loop as well. This is the info that I got from my crashes.

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.NullReferenceException: Object reference not set to an instance of an object.
at #Cg.#fo.#wH()
at #xh.#yk.#a7(Object , EventArgs )
at #xh.#yk.#wO(Object , Keys )
--- End of inner exception stack trace ---
at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
at System.Delegate.DynamicInvokeImpl(Object[] args)
at #xn.#5n.#ljb(Keys )
at #sn.#do.#gkb(List`1 )
at #sn.#do.#Teb()
at #Lg.#Ng.#rs()
at #tb.#zb.#8s()
at #tb.#zb.#jt(Object , EventArgs )
at #tb.#Db.#Dt()
at #tb.#Tb.#Rv(Object , EventArgs )
at System.Windows.Forms.Application.ThreadContext.System.Windows.Forms.UnsafeNativeMethods.IMsoComponent.FDoIdle(Int32 grfidlef)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at #tb.#Tb.Run()
at #tb.#zb.Run()
at #Lg.#mp.#Hyb(String , Boolean , Boolean )

Never mind, I have found the answer to this problem for the time being. Here for anyone that finds this topic and has this problem,
Read this

unless that is not it then well I tried.

I didnt even had error messages lol

I solved it on my side. Previously whenever osu started a non-fatal error message would appear saying that skin.ini was not properly configured. I checked my skin.ini and found that the author field was blank, typed some nonsense in and osu works now.

I guess the new version doesn't handle skin.ini misconfigurations the same as before and crashes might there be one. I suggest those who have this problem check their skin.ini, or rollback to an older version that could read the misconfigured file without crashing and change to another skin.