Pruning changes data retention, not consensus validation. It limits serving old blocks and searching history; it does not turn a full node into a lightweight wallet.
Ordinary IBD still obtains and processes historical blocks. Pruning itself skips no validation checks; any assumevalid optimization is a separate setting. [Bitcoin Core v29.0 — pruning configuration] [Bitcoin Core — validation] [Bitcoin Developer Guide — Block Chain]
After processing, eligible old block files and undo data used to reverse their changes may be removed. This neither deletes coins from the chain nor invalidates old transactions. [Bitcoin Core 0.11 release notes] [Bitcoin Core — prune blockchain RPC] [Bitcoin Core — validation]
The UTXO set and header index remain. The node knows current unspent outputs and block links even without retaining every original transaction. [Bitcoin Core 0.11 release notes] [Bitcoin Developer Guide — Block Chain]
Recent blocks and undo data provide a reorganization reserve. Going deeper than retained history may require obtaining data again or rebuilding state; storage limits do not define consensus finality. [Bitcoin Core 0.11 release notes] [Bitcoin Core — validation]
The automatic pruning target covers block and undo files. Databases, wallets and other files need additional space; whole-file removal and the safety reserve can cause target overshoot. [Bitcoin Core v29.0 — pruning configuration] [Bitcoin Core 0.11 release notes] [Bitcoin Core — getblockchaininfo]
A pruned Full Node rejects the same invalid blocks as an archival node with the same validation settings. A smaller archive does not weaken issuance checks or require trusting a peer's claims. [Bitcoin Core — validation] [Bitcoin Developer Guide — Block Chain]
The node cannot serve an old block it no longer has. It can still receive, validate and relay available new data; limited historical service does not disconnect it from the network. [Bitcoin Core 0.11 release notes] [Bitcoin Core — validation]
A wallet rescan requires blocks from the relevant period. Importing a key or descriptor does not restore deleted history; an older rescan requires obtaining the missing data. [Bitcoin Core v29.0 — pruning configuration] [Bitcoin Core 0.11 release notes]
Compatibility depends on the particular index and application. Bitcoin Core v29.0 does not allow txindex together with pruning; that does not imply all other indexes are forbidden. [Bitcoin Core v29.0 — pruning configuration]
Pruning reduces long-term disk needs, not ordinary initial history downloads. The UTXO set is not a private-key backup; secure wallet recovery remains a separate responsibility. [Bitcoin Core v29.0 — pruning configuration] [Bitcoin Core 0.11 release notes] [Bitcoin Developer Guide — Block Chain]
For the clearest picture, read this entry together with Initial block download, AssumeUTXO, Block propagation, Virtual byte (vbyte). The reverse links also lead from Initial block download, Compact Block Filters.