Unable to disable/make changes in User doc

Unable to disable or change password of any user through the “User” doc. It freezes and becomes unresponsive and after sometime throws 500 (INTERNAL SERVER ERROR).

Please suggest how to resolve this issue.

Traceback (most recent call last):
File “/home/frappe/frappe-bench/apps/frappe/frappe/desk/form/save.py”, line 22, in savedocs
doc.save()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 260, in save
return self._save(*args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 290, in _save
self.check_if_latest()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 622, in check_if_latest
where name = %s for update""".format(self.doctype), self.name, as_dict=True)
File “/home/frappe/frappe-bench/apps/frappe/frappe/database.py”, line 199, in sql
self._cursor.execute(query, values)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/cursors.py”, line 170, in execute
result = self._query(query)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/cursors.py”, line 328, in _query
conn.query(q)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/connections.py”, line 517, in query
self._affected_rows = self._read_query_result(unbuffered=unbuffered)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/connections.py”, line 732, in _read_query_result
result.read()
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/connections.py”, line 1075, in read
first_packet = self.connection._read_packet()
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/connections.py”, line 684, in _read_packet
packet.check_error()
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/protocol.py”, line 220, in check_error
err.raise_mysql_exception(self._data)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/err.py”, line 109, in raise_mysql_exception
raise errorclass(errno, errval)
InternalError: (1205, u’Lock wait timeout exceeded; try restarting transaction’)

request.js:318 Traceback (most recent call last):
File “/home/frappe/frappe-bench/apps/frappe/frappe/app.py”, line 62, in application
response = frappe.handler.handle()
File “/home/frappe/frappe-bench/apps/frappe/frappe/handler.py”, line 22, in handle
data = execute_cmd(cmd)
File “/home/frappe/frappe-bench/apps/frappe/frappe/handler.py”, line 55, in execute_cmd
return frappe.call(method, **frappe.form_dict)
File “/home/frappe/frappe-bench/apps/frappe/frappe/init.py”, line 942, in call
return fn(*args, **newargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/desk/form/save.py”, line 22, in savedocs
doc.save()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 260, in save
return self._save(*args, **kwargs)
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 290, in _save
self.check_if_latest()
File “/home/frappe/frappe-bench/apps/frappe/frappe/model/document.py”, line 622, in check_if_latest
where name = %s for update""".format(self.doctype), self.name, as_dict=True)
File “/home/frappe/frappe-bench/apps/frappe/frappe/database.py”, line 199, in sql
self._cursor.execute(query, values)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/cursors.py”, line 170, in execute
result = self._query(query)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/cursors.py”, line 328, in _query
conn.query(q)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/connections.py”, line 517, in query
self._affected_rows = self._read_query_result(unbuffered=unbuffered)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/connections.py”, line 732, in _read_query_result
result.read()
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/connections.py”, line 1075, in read
first_packet = self.connection._read_packet()
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/connections.py”, line 684, in _read_packet
packet.check_error()
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/protocol.py”, line 220, in check_error
err.raise_mysql_exception(self._data)
File “/home/frappe/frappe-bench/env/local/lib/python2.7/site-packages/pymysql/err.py”, line 109, in raise_mysql_exception
raise errorclass(errno, errval)
InternalError: (1205, u’Lock wait timeout exceeded; try restarting transaction’)