我之前在Windows 7上安装TortoiseHg 4.4.1-x64后也碰到了一模一样的问题——启动工作台时弹出日志提示，打开C:\Program Files\TortoiseHg\thgw.exe.log后看到这样的错误：

Traceback (most recent call last):
  File "thg", line 122, in 
  File "hgdemandimport\demandimportpy2.pyo", line 145, in getattr
  File "hgdemandimport\demandimportpy2.pyo", line 90, in _load
  File "hgdemandimport\demandimportpy2.pyo", line 41, in _hgextimport
  File "tortoisehg\hgqt\run.pyo", line 391, in 
  File "hgdemandimport\demandimportpy2.pyo", line 145, in getattr
  File "hgdemandimport\demandimportpy2.pyo", line 90, in _load
  File "hgdemandimport\demandimportpy2.pyo", line 41, in _hgextimport
  File "tortoisehg\hgqt\qtapp.pyo", line 18, in 
  File "hgdemandimport\demandimportpy2.pyo", line 167, in _demandimport
  File "hgdemandimport\demandimportpy2.pyo", line 41, in _hgextimport
  File "tortoisehg\hgqt\qtcore.pyo", line 53, in 
  File "hgdemandimport\demandimportpy2.pyo", line 167, in _demandimport
  File "hgdemandimport\demandimportpy2.pyo", line 41, in _hgextimport
  File "PyQt5\QtCore.pyo", line 12, in 
  File "PyQt5\QtCore.pyo", line 10, in __load
ImportError: DLL load failed: The specified module could not be found.

这个错误本质是PyQt5依赖的系统DLL缺失或不兼容，下面是我亲测有效的解决方案：

• 安装对应版本的VC++运行库：TortoiseHg 4.4.1依赖的PyQt5需要Microsoft Visual C++ 2015 Redistributable（x64版本）。去微软官方下载该运行库并安装，完成后重启电脑再尝试启动工作台。
• 修复TortoiseHg安装：找到当初的TortoiseHg安装包，右键点击选择「修复」选项，让安装程序自动检查并补全缺失的文件，尤其是PyQt5相关组件。
• 手动补充Qt核心DLL文件：如果修复无效，可以从另一台正常运行同版本TortoiseHg的Windows 7 x64机器上，复制Qt5Core.dll、Qt5Gui.dll等核心Qt DLL文件到C:\Program Files\TortoiseHg\目录下（注意要复制x64版本的文件）。
• 降级到兼容版本：如果以上方法都不行，建议降级到TortoiseHg 4.3.x版本，这个版本对Windows 7的兼容性更好，不会出现这类DLL依赖问题。

内容的提问来源于stack exchange，提问作者RahulGo8u