## The problem
Issue run-llama/llama_index#10697 (closed, 42 comments): ### Bug Description Any vector store which returns a TextNode to the query method, i get the following error ` File "pydantic/main.py", line 341, in pydantic.main.BaseModel.__init__ pydantic.error_wrappers.ValidationError: 1 validation error for NodeWithScore node Can't instantiate abstract class BaseNode with abstract methods get_content, get_metadata_str, get_type, hash, set_content (type=type_error)` ### Version v0.10.3 ### Steps to Reproduce ``` VectorStoreIndex.from_vector_store(vector_store) engine = clickhouse_vector_store().as_query_engine( similarity_top_k=10) response = engine.query(
## The verified fix
Maintainer nerdai confirmed the root cause is a polluted environment: legacy llama-index (0.9.x, llama_index.legacy) installed alongside the v0.10 namespaced packages breaks isinstance checks and class resolution ('Any legacy llama-index lingering in the virtual envs will certainly cause some issues'). Fix: create a fresh virtualenv and install only what you need (python -m venv venv; pip install llama-index; pip install [integration packages]), or pip uninstall llama-index then pip install llama-index --upgrade. Never mix llama_index.legacy imports with the new llama_index.core structure. Reporter gingerwizard confirmed: 'Resolved for me when i completely cleaned the env.'