Yosemite many issues

Question

Hi,
I hope someone can address these issues. I don't know where I can send my questions. I have iMac late 2013 with Yosemite, iPad mini 2014 with iOS8.1, Apple TV 2 and Time capsule.
Here is what I have problem sofar:
Airdrop - If I try to Airdrop a link from Safari from Mac. There is a window open, I can see my iPad and the page I try to send, and nothing happens, the system blocks for a while and after the window disappear. Theres is nothing coming on the iPad. If I try to send a photo or a file via AirDrop it works in both directions;
Markup - I attach a photo from my Mac , I can see the small Markup icon on the upper right corner of the photo. I open it and there are different tools appearing - again the windows freezes and I cannot do any modifications on the photo. I have to restart the mail app.
Sound - Every time I restart the Mac the sound icon is inactive - I have to go preferences/sound and I can see that the aggregate device is selected instead of internal speakers -  I have to change the sound output manually.
Launchpad - I have an empty app group which I cannot delete, nor change the names of other groups of apps.
Notification centre - cannot add or remove some of the stocks.
Finder - my iMac name is - iMacs iMac. All of a sudden it become iMacs iMac (2) and latter iMacs iMac (6). What are these numbers ?
Thank you very much,
If someone could at least tell me where to ask.
Nice day
PAvel
I had other issues i.e. wifi for which I found answers already

Answer 1

Testing in a new User will quickly tell you if the problem is system wide or if it's your User's folder that contains the problem.
CREATE A NEW USER
Go to System Preferences --> Create a New User in Users & Groups Switch to the New User by logging out/in or use Fast User Switching.
Enter your Apple ID and password.
Test Markup in Mail using the iCloud account.
Continue testing to see what works in the new User.
Do you still see the issue?
    If yes, then the problem is with your base files.
    If no, then the problem is in your User's folder.
Finder - my iMac name is - iMacs iMac. All of a sudden it become iMacs iMac (2) and latter iMacs iMac (6). What are these numbers ?
In System Preferences > Sharing you can see name. When Finder adds a number it indicates it's seeing another drive with the same name. You can select to rename but this could also be an indication of issues at the base level.
Do you have an external drive that could be used to clone your drive in case you need to do a clean install?