title: HDF5 Warnings When Accessing Xarray DataSet
body: <p>I'd like to understand what is causing the warning messages that I'm getting in the following scenario:</p>
  <p>In an earlier operation I've created some NetCDF files and saved them to disk using <code>xarray.to_netcdf()</code>.</p>
  <p>Lazy evaluation of these datasets is perfectly fine in a jupyter notebook and I receive no warnings/errors when:</p>
  <ul>
  <li>opening these <code>.nc</code> files via <code>ds = xarray.open_mfdataset('/path/to/files/*.nc')</code></li>
  <li>loading dimension data into memory via <code>ds.time.values</code></li>
  <li>lazy selection via <code>ds.sel(time=starttime)</code></li>
  </ul>
  <p>I seem to be able to do everything that I want to do in making calculations on memory loaded data. However I often receive the same set of errors when:</p>
  <ul>
  <li>loading data to plot via <code>ds.sel(time=starttime).SCALAR_DATA.plot()</code></li>
  <li>extracting/loading data via <code>ts = pd.Series(ds.SCALAR_DATA.loc[:,y,x], index=other_data.index)</code></li>
  </ul>
  <p>Note that despite these warnings the operations I perform do result in the desired outcomes (plots, timeseries structures, etc.).</p>
  <p>The common denominator in generating the following error seems to be loading data from the opened dataset. EDIT: It seems after some further experimentation that the package versions in my working environment may be causing some conflicts among those dependent on HDF5.</p>
  <p>The following errors repeat some number of times.</p>
  <pre><code>HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 1:
    #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute
      major: Attribute
      minor: Can't open object
    #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed
      major: Virtual Object Layer
      minor: Can't open object
    #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed
      major: Virtual Object Layer
      minor: Can't open object
    #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute
      major: Attribute
      minor: Can't open object
    #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header
      major: Attribute
      minor: Unable to initialize object
    #005: H5Oattribute.c line 494 in H5O__attr_open_by_name(): can't locate attribute: '_QuantizeBitGroomNumberOfSignificantDigits'
      major: Attribute
      minor: Object not found
  
  ...
  
  HDF5-DIAG: Error detected in HDF5 (1.12.2) thread 2:
    #000: H5A.c line 528 in H5Aopen_by_name(): can't open attribute
      major: Attribute
      minor: Can't open object
    #001: H5VLcallback.c line 1091 in H5VL_attr_open(): attribute open failed
      major: Virtual Object Layer
      minor: Can't open object
    #002: H5VLcallback.c line 1058 in H5VL__attr_open(): attribute open failed
      major: Virtual Object Layer
      minor: Can't open object
    #003: H5VLnative_attr.c line 130 in H5VL__native_attr_open(): can't open attribute
      major: Attribute
      minor: Can't open object
    #004: H5Aint.c line 545 in H5A__open_by_name(): unable to load attribute info from object header
      major: Attribute
      minor: Unable to initialize object
    #005: H5Oattribute.c line 476 in H5O__attr_open_by_name(): can't open attribute
      major: Attribute
      minor: Can't open object
    #006: H5Adense.c line 394 in H5A__dense_open(): can't locate attribute in name index
      major: Attribute
      minor: Object not found
  
  </code></pre>
  <p>Any suggestions on what might be causing these would be greatly appreciated.</p>