cannot start IntelliJ 2016.3 ultimate windows 10

After opening one of projects, React app to be exact, IntelliJ asked me about memory. Wrote me that -xmx parameter has too low value. I changed it to 1024 from previous 512, and I clicked to shutdown, and try to opened it again. After that it doesn't want to start. I reinstalled it with all my settings - again same. I reinstalled again, this time, I deleted all history, caches and settings from previous installations - still same issue. When I run from cmd `idea.bat` it throws this message:
`Error occurred during initialization of VM
Could not reserve enough space for 1048576KB object heap`.
There is not file `idea.log`, so I cannot add it here.
What should I do?