# ERROR: Invalid version specifier: '>=1.0,<2.0'

- **ID:** `python/pip-install-error-invalid-version-specifier`
- **Domain:** python
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The version specifier contains a syntax error, such as a missing comma or invalid operator, causing packaging to fail parsing.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 3.x | active | — | — |

## Workarounds

1. **** (99% success)
   ```
   pip install 'package>=1.0,<2.0'
   ```
2. **** (90% success)
   ```
   pip install 'package~=1.0'
   ```
3. **** (85% success)
   ```
   Refer to PEP 440 for valid version specifier syntax.
   ```

## Dead Ends

- **** — Quoting is already correct; the syntax itself is invalid. (90% fail)
- **** — Newer pip still enforces valid version specifier syntax. (95% fail)
- **** — Force reinstall does not bypass parsing. (95% fail)