Why is macbook slow after installing parallels desktop

How much free space is on your hard drive? How much ram is installed?

If there is not enough space on your machine, it will have more than it is desinged to carry. if you have to, save all your work and delete parrelells.

Parallels Desktop can also be configured to take a bunch of your Mac's resources. Do the slowdowns only happen when you have Parallels open and running?

An virtual machine puts a load on the host system. You are simulating a full machine environment, while at the same time running the native operating system and apps. The virtual machine takes resources (especially RAM) away from being useable by the host OS.

What are your MacBook Pro's specs?

Have you checked the number of tmp files in library --> Caldendar --> Calendar Sync Changes

I had almost 65.000 tmp files in this folder. System seems to work after having deleted them

I have the same issue. My MacBookPro started to run very slow a period of time after installing Paralells. Even when Paralells is not running. Not 100% sure it is Paralells but I have never seen anything like this on any of my other Mac's and the only difference is this one has Paralells installed.

I have the same problem , I installed the triel version of Paralall 9 in my mac already installed OX 10.9 , and my sistem became as the first PC i had in 1990 !! , and i still have 750GB free !!

so , any idea how to solve this problem ?

thanks😎