html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/4406#issuecomment-690922236,https://api.github.com/repos/pydata/xarray/issues/4406,690922236,MDEyOklzc3VlQ29tbWVudDY5MDkyMjIzNg==,6948919,2020-09-11T07:18:03Z,2020-09-11T07:18:03Z,NONE,"> Did this work reliably in the past? If so, any clues about specific versions of dask and/or netCDF that cause the issue would be helpful.
> 
> @TomAugspurger do you know off-hand if there have been any recent changes in Dask's scheduler that could have caused this?

I am new to xarray dask thing but month ago it was woking without issues. I recently reinstalled python and dont know if versions differs from previous one","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,694112301
https://github.com/pydata/xarray/issues/4406#issuecomment-690340047,https://api.github.com/repos/pydata/xarray/issues/4406,690340047,MDEyOklzc3VlQ29tbWVudDY5MDM0MDA0Nw==,6948919,2020-09-10T14:48:38Z,2020-09-10T14:48:38Z,NONE,"Using:

- xarray=0.16.0
- dask=2.25.0
- netcdf4=1.5.4

I am experiencing same when trying to write netcdf file using **to_netcdf()** on a files opened via xr.open_mfdataset with lock=None (which is default).

Then I tried to open files with **lock=False** and it worked like a charm. Issue have been gone for 100% of times.

**BUT**

Now I am facing different issue. Seems that **hdf5 IS NOT thread safe**, since I encounter **NetCDF: HDF error** while  applying different function on a netcdf files which were previously processed by another functions with **lock=False**.
Script just terminates not even reaching any calculation step in the code. seems like lock=False works opposite and file is in a **corrupted** mode?

This is the **BIGGEST** issue and needs resolve ASAP","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,694112301